Convert legacy Polyemer elements to class-based

This commit converts almost all Polymer elements from Polymer-function
based components to class-based components. There are few files which
should be converted manually after this commit.

Change-Id: I9e597e79053e0a6b5d5c0f1b54676d11b9d81db7
diff --git a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.js b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.js
index 10c876d..27b1cc4 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.js
+++ b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.js
@@ -14,13 +14,18 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-account-chip',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    */
+  class GrAccountChip extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-account-chip'; }
     /**
      * Fired to indicate a key was pressed while this chip was focused.
      *
@@ -34,51 +39,52 @@
      * @event remove
      */
 
-    properties: {
-      account: Object,
-      additionalText: String,
-      disabled: {
-        type: Boolean,
-        value: false,
-        reflectToAttribute: true,
-      },
-      removable: {
-        type: Boolean,
-        value: false,
-      },
-      showAvatar: {
-        type: Boolean,
-        reflectToAttribute: true,
-      },
-      transparentBackground: {
-        type: Boolean,
-        value: false,
-      },
-    },
-
-    behaviors: [
-      Gerrit.FireBehavior,
-    ],
+    static get properties() {
+      return {
+        account: Object,
+        additionalText: String,
+        disabled: {
+          type: Boolean,
+          value: false,
+          reflectToAttribute: true,
+        },
+        removable: {
+          type: Boolean,
+          value: false,
+        },
+        showAvatar: {
+          type: Boolean,
+          reflectToAttribute: true,
+        },
+        transparentBackground: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
 
     ready() {
+      super.ready();
       this._getHasAvatars().then(hasAvatars => {
         this.showAvatar = hasAvatars;
       });
-    },
+    }
 
     _getBackgroundClass(transparent) {
       return transparent ? 'transparentBackground' : '';
-    },
+    }
 
     _handleRemoveTap(e) {
       e.preventDefault();
       this.fire('remove', {account: this.account});
-    },
+    }
 
     _getHasAvatars() {
       return this.$.restAPI.getConfig().then(cfg => {
         return Promise.resolve(!!(cfg && cfg.plugin && cfg.plugin.has_avatars));
       });
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAccountChip.is, GrAccountChip);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-account-entry/gr-account-entry.js b/polygerrit-ui/app/elements/shared/gr-account-entry/gr-account-entry.js
index b2e0973..0ed3f19 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-entry/gr-account-entry.js
+++ b/polygerrit-ui/app/elements/shared/gr-account-entry/gr-account-entry.js
@@ -21,9 +21,10 @@
    * gr-account-entry is an element for entering account
    * and/or group with autocomplete support.
    */
-  Polymer({
-    is: 'gr-account-entry',
-
+  class GrAccountEntry extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-account-entry'; }
     /**
      * Fired when an account is entered.
      *
@@ -37,65 +38,70 @@
      *
      * @event account-text-changed
      */
-    properties: {
-      allowAnyInput: Boolean,
-      borderless: Boolean,
-      placeholder: String,
 
-      // suggestFrom = 0 to enable default suggestions.
-      suggestFrom: {
-        type: Number,
-        value: 0,
-      },
+    static get properties() {
+      return {
+        allowAnyInput: Boolean,
+        borderless: Boolean,
+        placeholder: String,
 
-      /** @type {!function(string): !Promise<Array<{name, value}>>} */
-      querySuggestions: {
-        type: Function,
-        notify: true,
-        value() {
-          return input => Promise.resolve([]);
+        // suggestFrom = 0 to enable default suggestions.
+        suggestFrom: {
+          type: Number,
+          value: 0,
         },
-      },
 
-      _config: Object,
-      /** The value of the autocomplete entry. */
-      _inputText: {
-        type: String,
-        observer: '_inputTextChanged',
-      },
+        /** @type {!function(string): !Promise<Array<{name, value}>>} */
+        querySuggestions: {
+          type: Function,
+          notify: true,
+          value() {
+            return input => Promise.resolve([]);
+          },
+        },
 
-    },
+        _config: Object,
+        /** The value of the autocomplete entry. */
+        _inputText: {
+          type: String,
+          observer: '_inputTextChanged',
+        },
+
+      };
+    }
 
     get focusStart() {
       return this.$.input.focusStart;
-    },
+    }
 
     focus() {
       this.$.input.focus();
-    },
+    }
 
     clear() {
       this.$.input.clear();
-    },
+    }
 
     setText(text) {
       this.$.input.setText(text);
-    },
+    }
 
     getText() {
       return this.$.input.text;
-    },
+    }
 
     _handleInputCommit(e) {
       this.fire('add', {value: e.detail.value});
       this.$.input.focus();
-    },
+    }
 
     _inputTextChanged(text) {
       if (text.length && this.allowAnyInput) {
         this.dispatchEvent(new CustomEvent(
             'account-text-changed', {bubbles: true, composed: true}));
       }
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAccountEntry.is, GrAccountEntry);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.js b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.js
index 418d2ea..3d96421 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.js
+++ b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.js
@@ -17,58 +17,65 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-account-label',
+  /**
+    * @appliesMixin Gerrit.DisplayNameMixin
+    * @appliesMixin Gerrit.TooltipMixin
+    */
+  class GrAccountLabel extends Polymer.mixinBehaviors( [
+    Gerrit.DisplayNameBehavior,
+    Gerrit.TooltipBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-account-label'; }
 
-    properties: {
+    static get properties() {
+      return {
       /**
        * @type {{ name: string, status: string }}
        */
-      account: Object,
-      avatarImageSize: {
-        type: Number,
-        value: 32,
-      },
-      title: {
-        type: String,
-        reflectToAttribute: true,
-        computed: '_computeAccountTitle(account, additionalText)',
-      },
-      additionalText: String,
-      hasTooltip: {
-        type: Boolean,
-        reflectToAttribute: true,
-        computed: '_computeHasTooltip(account)',
-      },
-      hideAvatar: {
-        type: Boolean,
-        value: false,
-      },
-      _serverConfig: {
-        type: Object,
-        value: null,
-      },
-    },
-
-    behaviors: [
-      Gerrit.DisplayNameBehavior,
-      Gerrit.TooltipBehavior,
-    ],
+        account: Object,
+        avatarImageSize: {
+          type: Number,
+          value: 32,
+        },
+        title: {
+          type: String,
+          reflectToAttribute: true,
+          computed: '_computeAccountTitle(account, additionalText)',
+        },
+        additionalText: String,
+        hasTooltip: {
+          type: Boolean,
+          reflectToAttribute: true,
+          computed: '_computeHasTooltip(account)',
+        },
+        hideAvatar: {
+          type: Boolean,
+          value: false,
+        },
+        _serverConfig: {
+          type: Object,
+          value: null,
+        },
+      };
+    }
 
     ready() {
+      super.ready();
       if (!this.additionalText) { this.additionalText = ''; }
       this.$.restAPI.getConfig()
           .then(config => { this._serverConfig = config; });
-    },
+    }
 
     _computeName(account, config) {
       return this.getUserName(config, account, false);
-    },
+    }
 
     _computeStatusTextLength(account, config) {
       // 35 as the max length of the name + status
       return Math.max(10, 35 - this._computeName(account, config).length);
-    },
+    }
 
     _computeAccountTitle(account, tooltip) {
       // Polymer 2: check for undefined
@@ -98,12 +105,12 @@
       }
 
       return result;
-    },
+    }
 
     _computeShowEmailClass(account) {
       if (!account || account.name || !account.email) { return ''; }
       return 'showEmail';
-    },
+    }
 
     _computeEmailStr(account) {
       if (!account || !account.email) {
@@ -113,11 +120,13 @@
         return '(' + account.email + ')';
       }
       return account.email;
-    },
+    }
 
     _computeHasTooltip(account) {
       // If an account has loaded to fire this method, then set to true.
       return !!account;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAccountLabel.is, GrAccountLabel);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-account-link/gr-account-link.js b/polygerrit-ui/app/elements/shared/gr-account-link/gr-account-link.js
index faaf9c3..0764669 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-link/gr-account-link.js
+++ b/polygerrit-ui/app/elements/shared/gr-account-link/gr-account-link.js
@@ -17,27 +17,34 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-account-link',
+  /**
+    * @appliesMixin Gerrit.BaseUrlMixin
+    */
+  class GrAccountLink extends Polymer.mixinBehaviors( [
+    Gerrit.BaseUrlBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-account-link'; }
 
-    properties: {
-      additionalText: String,
-      account: Object,
-      avatarImageSize: {
-        type: Number,
-        value: 32,
-      },
-    },
-
-    behaviors: [
-      Gerrit.BaseUrlBehavior,
-    ],
+    static get properties() {
+      return {
+        additionalText: String,
+        account: Object,
+        avatarImageSize: {
+          type: Number,
+          value: 32,
+        },
+      };
+    }
 
     _computeOwnerLink(account) {
       if (!account) { return; }
       return Gerrit.Nav.getUrlForOwner(
           account.email || account.username || account.name ||
           account._account_id);
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAccountLink.is, GrAccountLink);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-account-list/gr-account-list.js b/polygerrit-ui/app/elements/shared/gr-account-list/gr-account-list.js
index 9897105..48dddb0 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-list/gr-account-list.js
+++ b/polygerrit-ui/app/elements/shared/gr-account-list/gr-account-list.js
@@ -19,95 +19,101 @@
 
   const VALID_EMAIL_ALERT = 'Please input a valid email.';
 
-  Polymer({
-    is: 'gr-account-list',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    */
+  class GrAccountList extends Polymer.mixinBehaviors( [
+    // Used in the tests for gr-account-list and other elements tests.
+    Gerrit.FireBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-account-list'; }
     /**
      * Fired when user inputs an invalid email address.
      *
      * @event show-alert
      */
 
-    properties: {
-      accounts: {
-        type: Array,
-        value() { return []; },
-        notify: true,
-      },
-      change: Object,
-      filter: Function,
-      placeholder: String,
-      disabled: {
-        type: Function,
-        value: false,
-      },
+    static get properties() {
+      return {
+        accounts: {
+          type: Array,
+          value() { return []; },
+          notify: true,
+        },
+        change: Object,
+        filter: Function,
+        placeholder: String,
+        disabled: {
+          type: Function,
+          value: false,
+        },
 
-      /**
+        /**
        * Returns suggestions and convert them to list item
        * @type {Gerrit.GrSuggestionsProvider}
        */
-      suggestionsProvider: {
-        type: Object,
-      },
+        suggestionsProvider: {
+          type: Object,
+        },
 
-      /**
+        /**
        * Needed for template checking since value is initially set to null.
        * @type {?Object} */
-      pendingConfirmation: {
-        type: Object,
-        value: null,
-        notify: true,
-      },
-      readonly: {
-        type: Boolean,
-        value: false,
-      },
-      /**
+        pendingConfirmation: {
+          type: Object,
+          value: null,
+          notify: true,
+        },
+        readonly: {
+          type: Boolean,
+          value: false,
+        },
+        /**
        * When true, allows for non-suggested inputs to be added.
        */
-      allowAnyInput: {
-        type: Boolean,
-        value: false,
-      },
+        allowAnyInput: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * Array of values (groups/accounts) that are removable. When this prop is
        * undefined, all values are removable.
        */
-      removableValues: Array,
-      maxCount: {
-        type: Number,
-        value: 0,
-      },
+        removableValues: Array,
+        maxCount: {
+          type: Number,
+          value: 0,
+        },
 
-      /** Returns suggestion items
+        /** Returns suggestion items
       * @type {!function(string): Promise<Array<Gerrit.GrSuggestionItem>>}
       */
-      _querySuggestions: {
-        type: Function,
-        value() {
-          return this._getSuggestions.bind(this);
+        _querySuggestions: {
+          type: Function,
+          value() {
+            return this._getSuggestions.bind(this);
+          },
         },
-      },
-    },
+      };
+    }
 
-    behaviors: [
-      // Used in the tests for gr-account-list and other elements tests.
-      Gerrit.FireBehavior,
-    ],
-
-    listeners: {
-      remove: '_handleRemove',
-    },
+    created() {
+      super.created();
+      this.addEventListener('remove',
+          e => this._handleRemove(e));
+    }
 
     get accountChips() {
       return Array.from(
           Polymer.dom(this.root).querySelectorAll('gr-account-chip'));
-    },
+    }
 
     get focusStart() {
       return this.$.entry.focusStart;
-    },
+    }
 
     _getSuggestions(input) {
       const provider = this.suggestionsProvider;
@@ -122,11 +128,11 @@
         return suggestions.map(suggestion =>
           provider.makeSuggestionItem(suggestion));
       });
-    },
+    }
 
     _handleAdd(e) {
       this._addAccountItem(e.detail.value);
-    },
+    }
 
     _addAccountItem(item) {
       // Append new account or group to the accounts property. We add our own
@@ -162,14 +168,14 @@
       }
       this.pendingConfirmation = null;
       return true;
-    },
+    }
 
     confirmGroup(group) {
       group = Object.assign(
           {}, group, {confirmed: true, _pendingAdd: true, _group: true});
       this.push('accounts', group);
       this.pendingConfirmation = null;
-    },
+    }
 
     _computeChipClass(account) {
       const classes = [];
@@ -180,7 +186,7 @@
         classes.push('pendingAdd');
       }
       return classes.join(' ');
-    },
+    }
 
     _accountMatches(a, b) {
       if (a && b) {
@@ -192,7 +198,7 @@
         }
       }
       return a === b;
-    },
+    }
 
     _computeRemovable(account, readonly) {
       if (readonly) { return false; }
@@ -205,13 +211,13 @@
         return !!account._pendingAdd;
       }
       return true;
-    },
+    }
 
     _handleRemove(e) {
       const toRemove = e.detail.account;
       this._removeAccount(toRemove);
       this.$.entry.focus();
-    },
+    }
 
     _removeAccount(toRemove) {
       if (!toRemove || !this._computeRemovable(toRemove, this.readonly)) {
@@ -231,12 +237,12 @@
         }
       }
       console.warn('received remove event for missing account', toRemove);
-    },
+    }
 
     _getNativeInput(paperInput) {
       // In Polymer 2 inputElement isn't nativeInput anymore
       return paperInput.$.nativeInput || paperInput.inputElement;
-    },
+    }
 
     _handleInputKeydown(e) {
       const input = this._getNativeInput(e.detail.input);
@@ -254,7 +260,7 @@
           }
           break;
       }
-    },
+    }
 
     _handleChipKeydown(e) {
       const chip = e.target;
@@ -292,7 +298,7 @@
           }
           break;
       }
-    },
+    }
 
     /**
      * Submit the text of the entry as a reviewer value, if it exists. If it is
@@ -308,7 +314,7 @@
       const wasSubmitted = this._addAccountItem(text);
       if (wasSubmitted) { this.$.entry.clear(); }
       return wasSubmitted;
-    },
+    }
 
     additions() {
       return this.accounts.filter(account => {
@@ -320,10 +326,12 @@
           return {account};
         }
       });
-    },
+    }
 
     _computeEntryHidden(maxCount, accountsRecord, readonly) {
       return (maxCount && maxCount <= accountsRecord.base.length) || readonly;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAccountList.is, GrAccountList);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-alert/gr-alert.js b/polygerrit-ui/app/elements/shared/gr-alert/gr-alert.js
index e7c8b2c..433a57b 100644
--- a/polygerrit-ui/app/elements/shared/gr-alert/gr-alert.js
+++ b/polygerrit-ui/app/elements/shared/gr-alert/gr-alert.js
@@ -17,46 +17,51 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-alert',
-
+  class GrAlert extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-alert'; }
     /**
      * Fired when the action button is pressed.
      *
      * @event action
      */
 
-    properties: {
-      text: String,
-      actionText: String,
-      shown: {
-        type: Boolean,
-        value: true,
-        readOnly: true,
-        reflectToAttribute: true,
-      },
-      toast: {
-        type: Boolean,
-        value: true,
-        reflectToAttribute: true,
-      },
+    static get properties() {
+      return {
+        text: String,
+        actionText: String,
+        shown: {
+          type: Boolean,
+          value: true,
+          readOnly: true,
+          reflectToAttribute: true,
+        },
+        toast: {
+          type: Boolean,
+          value: true,
+          reflectToAttribute: true,
+        },
 
-      _hideActionButton: Boolean,
-      _boundTransitionEndHandler: {
-        type: Function,
-        value() { return this._handleTransitionEnd.bind(this); },
-      },
-      _actionCallback: Function,
-    },
+        _hideActionButton: Boolean,
+        _boundTransitionEndHandler: {
+          type: Function,
+          value() { return this._handleTransitionEnd.bind(this); },
+        },
+        _actionCallback: Function,
+      };
+    }
 
     attached() {
+      super.attached();
       this.addEventListener('transitionend', this._boundTransitionEndHandler);
-    },
+    }
 
     detached() {
+      super.detached();
       this.removeEventListener('transitionend',
           this._boundTransitionEndHandler);
-    },
+    }
 
     show(text, opt_actionText, opt_actionCallback) {
       this.text = text;
@@ -65,31 +70,33 @@
       this._actionCallback = opt_actionCallback;
       Gerrit.getRootElement().appendChild(this);
       this._setShown(true);
-    },
+    }
 
     hide() {
       this._setShown(false);
       if (this._hasZeroTransitionDuration()) {
         Gerrit.getRootElement().removeChild(this);
       }
-    },
+    }
 
     _hasZeroTransitionDuration() {
       const style = window.getComputedStyle(this);
       // transitionDuration is always given in seconds.
       const duration = Math.round(parseFloat(style.transitionDuration) * 100);
       return duration === 0;
-    },
+    }
 
     _handleTransitionEnd(e) {
       if (this.shown) { return; }
 
       Gerrit.getRootElement().removeChild(this);
-    },
+    }
 
     _handleActionTap(e) {
       e.preventDefault();
       if (this._actionCallback) { this._actionCallback(); }
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAlert.is, GrAlert);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.html b/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.html
index 9208068..2afbd82 100644
--- a/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.html
+++ b/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.html
@@ -17,6 +17,7 @@
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
 
+<link rel="import" href="../../../types/polymer-behaviors.js">
 <link rel="import" href="../../../behaviors/fire-behavior/fire-behavior.html">
 <link rel="import" href="../../../behaviors/keyboard-shortcut-behavior/keyboard-shortcut-behavior.html">
 <link rel="import" href="/bower_components/iron-dropdown/iron-dropdown.html">
diff --git a/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.js b/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.js
index b8c76ff..707c426 100644
--- a/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.js
+++ b/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.js
@@ -17,9 +17,19 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-autocomplete-dropdown',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    * @appliesMixin Gerrit.KeyboardShortcutMixin
+    * @appliesMixin Polymer.IronFitMixin
+    */
+  class GrAutocompleteDropdown extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+    Gerrit.KeyboardShortcutBehavior,
+    Polymer.IronFitBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-autocomplete-dropdown'; }
     /**
      * Fired when the dropdown is closed.
      *
@@ -32,57 +42,55 @@
      * @event item-selected
      */
 
-    properties: {
-      index: Number,
-      isHidden: {
-        type: Boolean,
-        value: true,
-        reflectToAttribute: true,
-      },
-      verticalOffset: {
-        type: Number,
-        value: null,
-      },
-      horizontalOffset: {
-        type: Number,
-        value: null,
-      },
-      suggestions: {
-        type: Array,
-        value: () => [],
-        observer: '_resetCursorStops',
-      },
-      _suggestionEls: Array,
-    },
+    static get properties() {
+      return {
+        index: Number,
+        isHidden: {
+          type: Boolean,
+          value: true,
+          reflectToAttribute: true,
+        },
+        verticalOffset: {
+          type: Number,
+          value: null,
+        },
+        horizontalOffset: {
+          type: Number,
+          value: null,
+        },
+        suggestions: {
+          type: Array,
+          value: () => [],
+          observer: '_resetCursorStops',
+        },
+        _suggestionEls: Array,
+      };
+    }
 
-    behaviors: [
-      Gerrit.FireBehavior,
-      Gerrit.KeyboardShortcutBehavior,
-      Polymer.IronFitBehavior,
-    ],
-
-    keyBindings: {
-      up: '_handleUp',
-      down: '_handleDown',
-      enter: '_handleEnter',
-      esc: '_handleEscape',
-      tab: '_handleTab',
-    },
+    get keyBindings() {
+      return {
+        up: '_handleUp',
+        down: '_handleDown',
+        enter: '_handleEnter',
+        esc: '_handleEscape',
+        tab: '_handleTab',
+      };
+    }
 
     close() {
       this.isHidden = true;
-    },
+    }
 
     open() {
       this.isHidden = false;
       this._resetCursorStops();
       // Refit should run after we call Polymer.flush inside _resetCursorStops
       this.refit();
-    },
+    }
 
     getCurrentText() {
       return this.getCursorTarget().dataset.value;
-    },
+    }
 
     _handleUp(e) {
       if (!this.isHidden) {
@@ -90,7 +98,7 @@
         e.stopPropagation();
         this.cursorUp();
       }
-    },
+    }
 
     _handleDown(e) {
       if (!this.isHidden) {
@@ -98,19 +106,19 @@
         e.stopPropagation();
         this.cursorDown();
       }
-    },
+    }
 
     cursorDown() {
       if (!this.isHidden) {
         this.$.cursor.next();
       }
-    },
+    }
 
     cursorUp() {
       if (!this.isHidden) {
         this.$.cursor.previous();
       }
-    },
+    }
 
     _handleTab(e) {
       e.preventDefault();
@@ -119,7 +127,7 @@
         trigger: 'tab',
         selected: this.$.cursor.target,
       });
-    },
+    }
 
     _handleEnter(e) {
       e.preventDefault();
@@ -128,12 +136,12 @@
         trigger: 'enter',
         selected: this.$.cursor.target,
       });
-    },
+    }
 
     _handleEscape() {
       this._fireClose();
       this.close();
-    },
+    }
 
     _handleClickItem(e) {
       e.preventDefault();
@@ -147,15 +155,15 @@
         trigger: 'click',
         selected,
       });
-    },
+    }
 
     _fireClose() {
       this.fire('dropdown-closed');
-    },
+    }
 
     getCursorTarget() {
       return this.$.cursor.target;
-    },
+    }
 
     _resetCursorStops() {
       if (this.suggestions.length > 0) {
@@ -168,14 +176,16 @@
       } else {
         this._suggestionEls = [];
       }
-    },
+    }
 
     _resetCursorIndex() {
       this.$.cursor.setCursorAtIndex(0);
-    },
+    }
 
     _computeLabelClass(item) {
       return item.label ? '' : 'hide';
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAutocompleteDropdown.is, GrAutocompleteDropdown);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.js b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.js
index da16e2b..a2c908a 100644
--- a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.js
+++ b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.js
@@ -20,9 +20,17 @@
   const TOKENIZE_REGEX = /(?:[^\s"]+|"[^"]*")+/g;
   const DEBOUNCE_WAIT_MS = 200;
 
-  Polymer({
-    is: 'gr-autocomplete',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    * @appliesMixin Gerrit.KeyboardShortcutMixin
+    */
+  class GrAutocomplete extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+    Gerrit.KeyboardShortcutBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-autocomplete'; }
     /**
      * Fired when a value is chosen.
      *
@@ -42,9 +50,10 @@
      * @event input-keydown
      */
 
-    properties: {
+    static get properties() {
+      return {
 
-      /**
+        /**
        * Query for requesting autocomplete suggestions. The function should
        * accept the input as a string parameter and return a promise. The
        * promise yields an array of suggestion objects with "name", "label",
@@ -55,170 +64,170 @@
        *
        * @type {function(string): Promise<?>}
        */
-      query: {
-        type: Function,
-        value() {
-          return function() {
-            return Promise.resolve([]);
-          };
+        query: {
+          type: Function,
+          value() {
+            return function() {
+              return Promise.resolve([]);
+            };
+          },
         },
-      },
 
-      /**
+        /**
        * The number of characters that must be typed before suggestions are
        * made. If threshold is zero, default suggestions are enabled.
        */
-      threshold: {
-        type: Number,
-        value: 1,
-      },
+        threshold: {
+          type: Number,
+          value: 1,
+        },
 
-      allowNonSuggestedValues: Boolean,
-      borderless: Boolean,
-      disabled: Boolean,
-      showSearchIcon: {
-        type: Boolean,
-        value: false,
-      },
-      // Vertical offset needed for a 1em font-size with no vertical padding.
-      // Inputs with additional padding will need to increase vertical offset.
-      verticalOffset: {
-        type: Number,
-        value: 20,
-      },
+        allowNonSuggestedValues: Boolean,
+        borderless: Boolean,
+        disabled: Boolean,
+        showSearchIcon: {
+          type: Boolean,
+          value: false,
+        },
+        // Vertical offset needed for a 1em font-size with no vertical padding.
+        // Inputs with additional padding will need to increase vertical offset.
+        verticalOffset: {
+          type: Number,
+          value: 20,
+        },
 
-      text: {
-        type: String,
-        value: '',
-        notify: true,
-      },
+        text: {
+          type: String,
+          value: '',
+          notify: true,
+        },
 
-      placeholder: String,
+        placeholder: String,
 
-      clearOnCommit: {
-        type: Boolean,
-        value: false,
-      },
+        clearOnCommit: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * When true, tab key autocompletes but does not fire the commit event.
        * When false, tab key not caught, and focus is removed from the element.
        * See Issue 4556, Issue 6645.
        */
-      tabComplete: {
-        type: Boolean,
-        value: false,
-      },
+        tabComplete: {
+          type: Boolean,
+          value: false,
+        },
 
-      value: {
-        type: String,
-        notify: true,
-      },
+        value: {
+          type: String,
+          notify: true,
+        },
 
-      /**
+        /**
        * Multi mode appends autocompleted entries to the value.
        * If false, autocompleted entries replace value.
        */
-      multi: {
-        type: Boolean,
-        value: false,
-      },
+        multi: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * When true and uncommitted text is left in the autocomplete input after
        * blurring, the text will appear red.
        */
-      warnUncommitted: {
-        type: Boolean,
-        value: false,
-      },
+        warnUncommitted: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * When true, querying for suggestions is not debounced w/r/t keypresses
        */
-      noDebounce: {
-        type: Boolean,
-        value: false,
-      },
+        noDebounce: {
+          type: Boolean,
+          value: false,
+        },
 
-      /** @type {?} */
-      _suggestions: {
-        type: Array,
-        value() { return []; },
-      },
+        /** @type {?} */
+        _suggestions: {
+          type: Array,
+          value() { return []; },
+        },
 
-      _suggestionEls: {
-        type: Array,
-        value() { return []; },
-      },
+        _suggestionEls: {
+          type: Array,
+          value() { return []; },
+        },
 
-      _index: Number,
-      _disableSuggestions: {
-        type: Boolean,
-        value: false,
-      },
-      _focused: {
-        type: Boolean,
-        value: false,
-      },
+        _index: Number,
+        _disableSuggestions: {
+          type: Boolean,
+          value: false,
+        },
+        _focused: {
+          type: Boolean,
+          value: false,
+        },
 
-      /** The DOM element of the selected suggestion. */
-      _selected: Object,
-    },
+        /** The DOM element of the selected suggestion. */
+        _selected: Object,
+      };
+    }
 
-    behaviors: [
-      Gerrit.FireBehavior,
-      Gerrit.KeyboardShortcutBehavior,
-    ],
-
-    observers: [
-      '_maybeOpenDropdown(_suggestions, _focused)',
-      '_updateSuggestions(text, threshold, noDebounce)',
-    ],
+    static get observers() {
+      return [
+        '_maybeOpenDropdown(_suggestions, _focused)',
+        '_updateSuggestions(text, threshold, noDebounce)',
+      ];
+    }
 
     get _nativeInput() {
       // In Polymer 2 inputElement isn't nativeInput anymore
       return this.$.input.$.nativeInput || this.$.input.inputElement;
-    },
+    }
 
     attached() {
+      super.attached();
       this.listen(document.body, 'click', '_handleBodyClick');
-    },
+    }
 
     detached() {
+      super.detached();
       this.unlisten(document.body, 'click', '_handleBodyClick');
       this.cancelDebouncer('update-suggestions');
-    },
+    }
 
     get focusStart() {
       return this.$.input;
-    },
+    }
 
     focus() {
       this._nativeInput.focus();
-    },
+    }
 
     selectAll() {
       const nativeInputElement = this._nativeInput;
       if (!this.$.input.value) { return; }
       nativeInputElement.setSelectionRange(0, this.$.input.value.length);
-    },
+    }
 
     clear() {
       this.text = '';
-    },
+    }
 
     _handleItemSelect(e) {
       // Let _handleKeydown deal with keyboard interaction.
       if (e.detail.trigger !== 'click') { return; }
       this._selected = e.detail.selected;
       this._commit();
-    },
+    }
 
     get _inputElement() {
       // Polymer2: this.$ can be undefined when this is first evaluated.
       return this.$ && this.$.input;
-    },
+    }
 
     /**
      * Set the text of the input without triggering the suggestion dropdown.
@@ -228,7 +237,7 @@
       this._disableSuggestions = true;
       this.text = text;
       this._disableSuggestions = false;
-    },
+    }
 
     _onInputFocus() {
       this._focused = true;
@@ -236,14 +245,14 @@
       this.$.input.classList.remove('warnUncommitted');
       // Needed so that --paper-input-container-input updated style is applied.
       this.updateStyles();
-    },
+    }
 
     _onInputBlur() {
       this.$.input.classList.toggle('warnUncommitted',
           this.warnUncommitted && this.text.length && !this._focused);
       // Needed so that --paper-input-container-input updated style is applied.
       this.updateStyles();
-    },
+    }
 
     _updateSuggestions(text, threshold, noDebounce) {
       // Polymer 2: check for undefined
@@ -280,18 +289,18 @@
       } else {
         this.debounce('update-suggestions', update, DEBOUNCE_WAIT_MS);
       }
-    },
+    }
 
     _maybeOpenDropdown(suggestions, focused) {
       if (suggestions.length > 0 && focused) {
         return this.$.suggestions.open();
       }
       return this.$.suggestions.close();
-    },
+    }
 
     _computeClass(borderless) {
       return borderless ? 'borderless' : '';
-    },
+    }
 
     /**
      * _handleKeydown used for key handling in the this.$.input AND all child
@@ -338,7 +347,7 @@
           this._suggestions = [];
       }
       this.fire('input-keydown', {keyCode: e.keyCode, input: this.$.input});
-    },
+    }
 
     _cancel() {
       if (this._suggestions.length) {
@@ -346,7 +355,7 @@
       } else {
         this.fire('cancel');
       }
-    },
+    }
 
     /**
      * @param {boolean=} opt_tabComplete
@@ -358,7 +367,7 @@
 
       this._selected = this.$.suggestions.getCursorTarget();
       this._commit(opt_tabComplete);
-    },
+    }
 
     _updateValue(suggestion, suggestions) {
       if (!suggestion) { return; }
@@ -372,7 +381,7 @@
       } else {
         this.value = completed;
       }
-    },
+    }
 
     _handleBodyClick(e) {
       const eventPath = Polymer.dom(e).path;
@@ -382,13 +391,13 @@
         }
       }
       this._focused = false;
-    },
+    }
 
     _handleSuggestionTap(e) {
       e.stopPropagation();
       this.$.cursor.setCursor(e.target);
       this._commit();
-    },
+    }
 
     /**
      * Commits the suggestion, optionally firing the commit event.
@@ -424,10 +433,12 @@
       }
 
       this._textChangedSinceCommit = false;
-    },
+    }
 
     _computeShowSearchIconClass(showSearchIcon) {
       return showSearchIcon ? 'showSearchIcon' : '';
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAutocomplete.is, GrAutocomplete);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar.js b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar.js
index bf56382..e57ba33 100644
--- a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar.js
+++ b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar.js
@@ -17,29 +17,35 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-avatar',
+  /**
+    * @appliesMixin Gerrit.BaseUrlMixin
+    */
+  class GrAvatar extends Polymer.mixinBehaviors( [
+    Gerrit.BaseUrlBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-avatar'; }
 
-    properties: {
-      account: {
-        type: Object,
-        observer: '_accountChanged',
-      },
-      imageSize: {
-        type: Number,
-        value: 16,
-      },
-      _hasAvatars: {
-        type: Boolean,
-        value: false,
-      },
-    },
-
-    behaviors: [
-      Gerrit.BaseUrlBehavior,
-    ],
+    static get properties() {
+      return {
+        account: {
+          type: Object,
+          observer: '_accountChanged',
+        },
+        imageSize: {
+          type: Number,
+          value: 16,
+        },
+        _hasAvatars: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
 
     attached() {
+      super.attached();
       Promise.all([
         this._getConfig(),
         Gerrit.awaitPluginsLoaded(),
@@ -48,15 +54,15 @@
 
         this._updateAvatarURL();
       });
-    },
+    }
 
     _getConfig() {
       return this.$.restAPI.getConfig();
-    },
+    }
 
     _accountChanged(account) {
       this._updateAvatarURL();
-    },
+    }
 
     _updateAvatarURL() {
       if (!this._hasAvatars || !this.account) {
@@ -69,12 +75,12 @@
       if (url) {
         this.style.backgroundImage = 'url("' + url + '")';
       }
-    },
+    }
 
     _getAccounts(account) {
       return account._account_id || account.email || account.username ||
           account.name;
-    },
+    }
 
     _buildAvatarURL(account) {
       if (!account) { return ''; }
@@ -87,6 +93,8 @@
       return this.getBaseUrl() + '/accounts/' +
         encodeURIComponent(this._getAccounts(account)) +
         '/avatar?s=' + this.imageSize;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrAvatar.is, GrAvatar);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-button/gr-button.js b/polygerrit-ui/app/elements/shared/gr-button/gr-button.js
index 99d4fe4..1de704a 100644
--- a/polygerrit-ui/app/elements/shared/gr-button/gr-button.js
+++ b/polygerrit-ui/app/elements/shared/gr-button/gr-button.js
@@ -17,65 +17,77 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-button',
+  /**
+    * @appliesMixin Gerrit.KeyboardShortcutMixin
+    * @appliesMixin Gerrit.TooltipMixin
+    */
+  class GrButton extends Polymer.mixinBehaviors( [
+    Gerrit.KeyboardShortcutBehavior,
+    Gerrit.TooltipBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-button'; }
 
-    properties: {
-      tooltip: String,
-      downArrow: {
-        type: Boolean,
-        reflectToAttribute: true,
-      },
-      link: {
-        type: Boolean,
-        value: false,
-        reflectToAttribute: true,
-      },
-      loading: {
-        type: Boolean,
-        value: false,
-        reflectToAttribute: true,
-      },
-      disabled: {
-        type: Boolean,
-        observer: '_disabledChanged',
-        reflectToAttribute: true,
-      },
-      noUppercase: {
-        type: Boolean,
-        value: false,
-      },
-      _enabledTabindex: {
-        type: String,
-        value: '0',
-      },
-    },
+    static get properties() {
+      return {
+        tooltip: String,
+        downArrow: {
+          type: Boolean,
+          reflectToAttribute: true,
+        },
+        link: {
+          type: Boolean,
+          value: false,
+          reflectToAttribute: true,
+        },
+        loading: {
+          type: Boolean,
+          value: false,
+          reflectToAttribute: true,
+        },
+        disabled: {
+          type: Boolean,
+          observer: '_disabledChanged',
+          reflectToAttribute: true,
+        },
+        noUppercase: {
+          type: Boolean,
+          value: false,
+        },
+        _enabledTabindex: {
+          type: String,
+          value: '0',
+        },
+      };
+    }
 
-    listeners: {
-      click: '_handleAction',
-      keydown: '_handleKeydown',
-    },
+    static get observers() {
+      return [
+        '_computeDisabled(disabled, loading)',
+      ];
+    }
 
-    observers: [
-      '_computeDisabled(disabled, loading)',
-    ],
+    created() {
+      super.created();
+      this.addEventListener('click',
+          e => this._handleAction(e));
+      this.addEventListener('keydown',
+          e => this._handleKeydown(e));
+    }
 
-    behaviors: [
-      Gerrit.KeyboardShortcutBehavior,
-      Gerrit.TooltipBehavior,
-    ],
-
-    hostAttributes: {
-      role: 'button',
-      tabindex: '0',
-    },
+    ready() {
+      super.ready();
+      this._ensureAttribute('role', 'button');
+      this._ensureAttribute('tabindex', '0');
+    }
 
     _handleAction(e) {
       if (this.disabled) {
         e.preventDefault();
         e.stopImmediatePropagation();
       }
-    },
+    }
 
     _disabledChanged(disabled) {
       if (disabled) {
@@ -83,11 +95,11 @@
       }
       this.setAttribute('tabindex', disabled ? '-1' : this._enabledTabindex);
       this.updateStyles();
-    },
+    }
 
     _computeDisabled(disabled, loading) {
       return disabled || loading;
-    },
+    }
 
     _handleKeydown(e) {
       if (this.modifierPressed(e)) { return; }
@@ -98,6 +110,8 @@
         e.stopPropagation();
         this.click();
       }
-    },
-  });
+    }
+  }
+
+  customElements.define(GrButton.is, GrButton);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star.js b/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star.js
index a83bc2b..05e759f 100644
--- a/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star.js
+++ b/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star.js
@@ -17,31 +17,34 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-change-star',
-
+  class GrChangeStar extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-change-star'; }
     /**
      * Fired when star state is toggled.
      *
      * @event toggle-star
      */
 
-    properties: {
+    static get properties() {
+      return {
       /** @type {?} */
-      change: {
-        type: Object,
-        notify: true,
-      },
-    },
+        change: {
+          type: Object,
+          notify: true,
+        },
+      };
+    }
 
     _computeStarClass(starred) {
       return starred ? 'active' : '';
-    },
+    }
 
     _computeStarIcon(starred) {
       // Hollow star is used to indicate inactive state.
       return `gr-icons:star${starred ? '' : '-border'}`;
-    },
+    }
 
     toggleStar() {
       const newVal = !this.change.starred;
@@ -51,6 +54,8 @@
         composed: true,
         detail: {change: this.change, starred: newVal},
       }));
-    },
-  });
+    }
+  }
+
+  customElements.define(GrChangeStar.is, GrChangeStar);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-change-status/gr-change-status.js b/polygerrit-ui/app/elements/shared/gr-change-status/gr-change-status.js
index 3afbe54..01af9eb 100644
--- a/polygerrit-ui/app/elements/shared/gr-change-status/gr-change-status.js
+++ b/polygerrit-ui/app/elements/shared/gr-change-status/gr-change-status.js
@@ -32,35 +32,39 @@
   const PRIVATE_TOOLTIP = 'This change is only visible to its owner and ' +
       'current reviewers (or anyone with "View Private Changes" permission).';
 
-  Polymer({
-    is: 'gr-change-status',
+  class GrChangeStatus extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-change-status'; }
 
-    properties: {
-      flat: {
-        type: Boolean,
-        value: false,
-        reflectToAttribute: true,
-      },
-      status: {
-        type: String,
-        observer: '_updateChipDetails',
-      },
-      tooltipText: {
-        type: String,
-        value: '',
-      },
-    },
+    static get properties() {
+      return {
+        flat: {
+          type: Boolean,
+          value: false,
+          reflectToAttribute: true,
+        },
+        status: {
+          type: String,
+          observer: '_updateChipDetails',
+        },
+        tooltipText: {
+          type: String,
+          value: '',
+        },
+      };
+    }
 
     _computeStatusString(status) {
       if (status === ChangeStates.WIP && !this.flat) {
         return 'Work in Progress';
       }
       return status;
-    },
+    }
 
     _toClassName(str) {
       return str.toLowerCase().replace(/\s/g, '-');
-    },
+    }
 
     _updateChipDetails(status, previousStatus) {
       if (previousStatus) {
@@ -79,6 +83,8 @@
           this.tooltipText = '';
           break;
       }
-    },
-  });
+    }
+  }
+
+  customElements.define(GrChangeStatus.is, GrChangeStatus);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.js b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.js
index ff5576cb..c106acd 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.js
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.js
@@ -20,9 +20,22 @@
   const UNRESOLVED_EXPAND_COUNT = 5;
   const NEWLINE_PATTERN = /\n/g;
 
-  Polymer({
-    is: 'gr-comment-thread',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    * @appliesMixin Gerrit.KeyboardShortcutMixin
+    * @appliesMixin Gerrit.PathListMixin
+    */
+  class GrCommentThread extends Polymer.mixinBehaviors( [
+    /**
+       * Not used in this element rather other elements tests
+       */
+    Gerrit.FireBehavior,
+    Gerrit.KeyboardShortcutBehavior,
+    Gerrit.PathListBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-comment-thread'; }
     /**
      * Fired when the thread should be discarded.
      *
@@ -36,122 +49,122 @@
      */
 
     /**
-      * gr-comment-thread exposes the following attributes that allow a
-      * diff widget like gr-diff to show the thread in the right location:
-      *
-      * line-num:
-      *     1-based line number or undefined if it refers to the entire file.
-      *
-      * comment-side:
-      *     "left" or "right". These indicate which of the two diffed versions
-      *     the comment relates to. In the case of unified diff, the left
-      *     version is the one whose line number column is further to the left.
-      *
-      * range:
-      *     The range of text that the comment refers to (start_line,
-      *     start_character, end_line, end_character), serialized as JSON. If
-      *     set, range's end_line will have the same value as line-num. Line
-      *     numbers are 1-based, char numbers are 0-based. The start position
-      *     (start_line, start_character) is inclusive, and the end position
-      *     (end_line, end_character) is exclusive.
-      */
-    properties: {
-      changeNum: String,
-      comments: {
-        type: Array,
-        value() { return []; },
-      },
-      /**
+              * gr-comment-thread exposes the following attributes that allow a
+              * diff widget like gr-diff to show the thread in the right location:
+              *
+              * line-num:
+              *     1-based line number or undefined if it refers to the entire file.
+              *
+              * comment-side:
+              *     "left" or "right". These indicate which of the two diffed versions
+              *     the comment relates to. In the case of unified diff, the left
+              *     version is the one whose line number column is further to the left.
+              *
+              * range:
+              *     The range of text that the comment refers to (start_line,
+              *     start_character, end_line, end_character), serialized as JSON. If
+              *     set, range's end_line will have the same value as line-num. Line
+              *     numbers are 1-based, char numbers are 0-based. The start position
+              *     (start_line, start_character) is inclusive, and the end position
+              *     (end_line, end_character) is exclusive.
+              */
+    static get properties() {
+      return {
+        changeNum: String,
+        comments: {
+          type: Array,
+          value() { return []; },
+        },
+        /**
        * @type {?{start_line: number, start_character: number, end_line: number,
        *          end_character: number}}
        */
-      range: {
-        type: Object,
-        reflectToAttribute: true,
-      },
-      keyEventTarget: {
-        type: Object,
-        value() { return document.body; },
-      },
-      commentSide: {
-        type: String,
-        reflectToAttribute: true,
-      },
-      patchNum: String,
-      path: String,
-      projectName: {
-        type: String,
-        observer: '_projectNameChanged',
-      },
-      hasDraft: {
-        type: Boolean,
-        notify: true,
-        reflectToAttribute: true,
-      },
-      isOnParent: {
-        type: Boolean,
-        value: false,
-      },
-      parentIndex: {
-        type: Number,
-        value: null,
-      },
-      rootId: {
-        type: String,
-        notify: true,
-        computed: '_computeRootId(comments.*)',
-      },
-      /**
+        range: {
+          type: Object,
+          reflectToAttribute: true,
+        },
+        keyEventTarget: {
+          type: Object,
+          value() { return document.body; },
+        },
+        commentSide: {
+          type: String,
+          reflectToAttribute: true,
+        },
+        patchNum: String,
+        path: String,
+        projectName: {
+          type: String,
+          observer: '_projectNameChanged',
+        },
+        hasDraft: {
+          type: Boolean,
+          notify: true,
+          reflectToAttribute: true,
+        },
+        isOnParent: {
+          type: Boolean,
+          value: false,
+        },
+        parentIndex: {
+          type: Number,
+          value: null,
+        },
+        rootId: {
+          type: String,
+          notify: true,
+          computed: '_computeRootId(comments.*)',
+        },
+        /**
        * If this is true, the comment thread also needs to have the change and
        * line properties property set
        */
-      showFilePath: {
-        type: Boolean,
-        value: false,
-      },
-      /** Necessary only if showFilePath is true or when used with gr-diff */
-      lineNum: {
-        type: Number,
-        reflectToAttribute: true,
-      },
-      unresolved: {
-        type: Boolean,
-        notify: true,
-        reflectToAttribute: true,
-      },
-      _showActions: Boolean,
-      _lastComment: Object,
-      _orderedComments: Array,
-      _projectConfig: Object,
-    },
+        showFilePath: {
+          type: Boolean,
+          value: false,
+        },
+        /** Necessary only if showFilePath is true or when used with gr-diff */
+        lineNum: {
+          type: Number,
+          reflectToAttribute: true,
+        },
+        unresolved: {
+          type: Boolean,
+          notify: true,
+          reflectToAttribute: true,
+        },
+        _showActions: Boolean,
+        _lastComment: Object,
+        _orderedComments: Array,
+        _projectConfig: Object,
+      };
+    }
 
-    behaviors: [
-      /**
-       * Not used in this element rather other elements tests
-       */
-      Gerrit.FireBehavior,
-      Gerrit.KeyboardShortcutBehavior,
-      Gerrit.PathListBehavior,
-    ],
+    static get observers() {
+      return [
+        '_commentsChanged(comments.*)',
+      ];
+    }
 
-    listeners: {
-      'comment-update': '_handleCommentUpdate',
-    },
+    get keyBindings() {
+      return {
+        'e shift+e': '_handleEKey',
+      };
+    }
 
-    observers: [
-      '_commentsChanged(comments.*)',
-    ],
-
-    keyBindings: {
-      'e shift+e': '_handleEKey',
-    },
+    created() {
+      super.created();
+      this.addEventListener('comment-update',
+          e => this._handleCommentUpdate(e));
+    }
 
     attached() {
+      super.attached();
       this._getLoggedIn().then(loggedIn => {
         this._showActions = loggedIn;
       });
       this._setInitialExpandedState();
-    },
+    }
 
     addOrEditDraft(opt_lineNum, opt_range) {
       const lastComment = this.comments[this.comments.length - 1] || {};
@@ -169,39 +182,39 @@
         const unresolved = lastComment ? lastComment.unresolved : undefined;
         this.addDraft(opt_lineNum, range, unresolved);
       }
-    },
+    }
 
     addDraft(opt_lineNum, opt_range, opt_unresolved) {
       const draft = this._newDraft(opt_lineNum, opt_range);
       draft.__editing = true;
       draft.unresolved = opt_unresolved === false ? opt_unresolved : true;
       this.push('comments', draft);
-    },
+    }
 
     fireRemoveSelf() {
       this.dispatchEvent(new CustomEvent('thread-discard',
           {detail: {rootId: this.rootId}, bubbles: false}));
-    },
+    }
 
     _getDiffUrlForComment(projectName, changeNum, path, patchNum) {
       return Gerrit.Nav.getUrlForDiffById(changeNum,
           projectName, path, patchNum,
           null, this.lineNum);
-    },
+    }
 
     _computeDisplayPath(path) {
       const lineString = this.lineNum ? `#${this.lineNum}` : '';
       return this.computeDisplayPath(path) + lineString;
-    },
+    }
 
     _getLoggedIn() {
       return this.$.restAPI.getLoggedIn();
-    },
+    }
 
     _commentsChanged() {
       this._orderedComments = this._sortedComments(this.comments);
       this.updateThreadProperties();
-    },
+    }
 
     updateThreadProperties() {
       if (this._orderedComments.length) {
@@ -209,16 +222,16 @@
         this.unresolved = this._lastComment.unresolved;
         this.hasDraft = this._lastComment.__draft;
       }
-    },
+    }
 
     _hideActions(_showActions, _lastComment) {
       return !_showActions || !_lastComment || !!_lastComment.__draft ||
         !!_lastComment.robot_id;
-    },
+    }
 
     _getLastComment() {
       return this._orderedComments[this._orderedComments.length - 1] || {};
-    },
+    }
 
     _handleEKey(e) {
       if (this.shouldSuppressKeyboardShortcut(e)) { return; }
@@ -231,7 +244,7 @@
         if (this.modifierPressed(e)) { return; }
         this._expandCollapseComments(false);
       }
-    },
+    }
 
     _expandCollapseComments(actionIsCollapse) {
       const comments =
@@ -239,7 +252,7 @@
       for (const comment of comments) {
         comment.collapsed = actionIsCollapse;
       }
-    },
+    }
 
     /**
      * Sets the initial state of the comment thread.
@@ -259,7 +272,7 @@
           comment.collapsed = !isRobotComment && resolvedThread;
         }
       }
-    },
+    }
 
     _sortedComments(comments) {
       return comments.slice().sort((c1, c2) => {
@@ -275,7 +288,7 @@
         // If same date, fall back to sorting by id.
         return dateCompare ? dateCompare : c1.id.localeCompare(c2.id);
       });
-    },
+    }
 
     _createReplyComment(parent, content, opt_isEditing,
         opt_unresolved) {
@@ -309,11 +322,11 @@
           commentEl.save();
         }, 1);
       }
-    },
+    }
 
     _isDraft(comment) {
       return !!comment.__draft;
-    },
+    }
 
     /**
      * @param {boolean=} opt_quote
@@ -326,25 +339,25 @@
         quoteStr = '> ' + msg.replace(NEWLINE_PATTERN, '\n> ') + '\n\n';
       }
       this._createReplyComment(comment, quoteStr, true, comment.unresolved);
-    },
+    }
 
     _handleCommentReply(e) {
       this._processCommentReply();
-    },
+    }
 
     _handleCommentQuote(e) {
       this._processCommentReply(true);
-    },
+    }
 
     _handleCommentAck(e) {
       const comment = this._lastComment;
       this._createReplyComment(comment, 'Ack', false, false);
-    },
+    }
 
     _handleCommentDone(e) {
       const comment = this._lastComment;
       this._createReplyComment(comment, 'Done', false, false);
-    },
+    }
 
     _handleCommentFix(e) {
       const comment = e.detail.comment;
@@ -352,7 +365,7 @@
       const quoteStr = '> ' + msg.replace(NEWLINE_PATTERN, '\n> ') + '\n\n';
       const response = quoteStr + 'Please Fix';
       this._createReplyComment(comment, response, false, true);
-    },
+    }
 
     _commentElWithDraftID(id) {
       const els = Polymer.dom(this.root).querySelectorAll('gr-comment');
@@ -362,7 +375,7 @@
         }
       }
       return null;
-    },
+    }
 
     _newReply(inReplyTo, opt_lineNum, opt_message, opt_unresolved,
         opt_range) {
@@ -376,7 +389,7 @@
         d.unresolved = opt_unresolved;
       }
       return d;
-    },
+    }
 
     /**
      * @param {number=} opt_lineNum
@@ -402,12 +415,12 @@
         d.parent = this.parentIndex;
       }
       return d;
-    },
+    }
 
     _getSide(isOnParent) {
       if (isOnParent) { return 'PARENT'; }
       return 'REVISION';
-    },
+    }
 
     _computeRootId(comments) {
       // Keep the root ID even if the comment was removed, so that notification
@@ -415,7 +428,7 @@
       if (!comments.base.length) { return this.rootId; }
       const rootComment = comments.base[0];
       return rootComment.id || rootComment.__draftID;
-    },
+    }
 
     _handleCommentDiscard(e) {
       const diffCommentEl = Polymer.dom(e).rootTarget;
@@ -445,13 +458,13 @@
               changeComment.message);
         }
       }
-    },
+    }
 
     _handleCommentSavedOrDiscarded(e) {
       this.dispatchEvent(new CustomEvent('thread-changed',
           {detail: {rootId: this.rootId, path: this.path},
             bubbles: false}));
-    },
+    }
 
     _handleCommentUpdate(e) {
       const comment = e.detail.comment;
@@ -467,7 +480,7 @@
       // observers, the this.set() call above will not cause a thread update in
       // some situations.
       this.updateThreadProperties();
-    },
+    }
 
     _indexOf(comment, arr) {
       for (let i = 0; i < arr.length; i++) {
@@ -478,11 +491,11 @@
         }
       }
       return -1;
-    },
+    }
 
     _computeHostClass(unresolved) {
       return unresolved ? 'unresolved' : '';
-    },
+    }
 
     /**
      * Load the project config when a project name has been provided.
@@ -493,6 +506,8 @@
       this.$.restAPI.getProjectConfig(name).then(config => {
         this._projectConfig = config;
       });
-    },
-  });
+    }
+  }
+
+  customElements.define(GrCommentThread.is, GrCommentThread);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.js b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.js
index a5c0c0b..dd2855c 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.js
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.js
@@ -31,9 +31,17 @@
 
   const FILE = 'FILE';
 
-  Polymer({
-    is: 'gr-comment',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    * @appliesMixin Gerrit.KeyboardShortcutMixin
+    */
+  class GrComment extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+    Gerrit.KeyboardShortcutBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-comment'; }
     /**
      * Fired when the create fix comment action is triggered.
      *
@@ -64,109 +72,111 @@
      * @event comment-anchor-tap
      */
 
-    properties: {
-      changeNum: String,
-      /** @type {?} */
-      comment: {
-        type: Object,
-        notify: true,
-        observer: '_commentChanged',
-      },
-      isRobotComment: {
-        type: Boolean,
-        value: false,
-        reflectToAttribute: true,
-      },
-      disabled: {
-        type: Boolean,
-        value: false,
-        reflectToAttribute: true,
-      },
-      draft: {
-        type: Boolean,
-        value: false,
-        observer: '_draftChanged',
-      },
-      editing: {
-        type: Boolean,
-        value: false,
-        observer: '_editingChanged',
-      },
-      discarding: {
-        type: Boolean,
-        value: false,
-        reflectToAttribute: true,
-      },
-      hasChildren: Boolean,
-      patchNum: String,
-      showActions: Boolean,
-      _showHumanActions: Boolean,
-      _showRobotActions: Boolean,
-      collapsed: {
-        type: Boolean,
-        value: true,
-        observer: '_toggleCollapseClass',
-      },
-      /** @type {?} */
-      projectConfig: Object,
-      robotButtonDisabled: Boolean,
-      _isAdmin: {
-        type: Boolean,
-        value: false,
-      },
+    static get properties() {
+      return {
+        changeNum: String,
+        /** @type {?} */
+        comment: {
+          type: Object,
+          notify: true,
+          observer: '_commentChanged',
+        },
+        isRobotComment: {
+          type: Boolean,
+          value: false,
+          reflectToAttribute: true,
+        },
+        disabled: {
+          type: Boolean,
+          value: false,
+          reflectToAttribute: true,
+        },
+        draft: {
+          type: Boolean,
+          value: false,
+          observer: '_draftChanged',
+        },
+        editing: {
+          type: Boolean,
+          value: false,
+          observer: '_editingChanged',
+        },
+        discarding: {
+          type: Boolean,
+          value: false,
+          reflectToAttribute: true,
+        },
+        hasChildren: Boolean,
+        patchNum: String,
+        showActions: Boolean,
+        _showHumanActions: Boolean,
+        _showRobotActions: Boolean,
+        collapsed: {
+          type: Boolean,
+          value: true,
+          observer: '_toggleCollapseClass',
+        },
+        /** @type {?} */
+        projectConfig: Object,
+        robotButtonDisabled: Boolean,
+        _isAdmin: {
+          type: Boolean,
+          value: false,
+        },
 
-      _xhrPromise: Object, // Used for testing.
-      _messageText: {
-        type: String,
-        value: '',
-        observer: '_messageTextChanged',
-      },
-      commentSide: String,
-      side: String,
+        _xhrPromise: Object, // Used for testing.
+        _messageText: {
+          type: String,
+          value: '',
+          observer: '_messageTextChanged',
+        },
+        commentSide: String,
+        side: String,
 
-      resolved: Boolean,
+        resolved: Boolean,
 
-      _numPendingDraftRequests: {
-        type: Object,
-        value:
+        _numPendingDraftRequests: {
+          type: Object,
+          value:
             {number: 0}, // Intentional to share the object across instances.
-      },
+        },
 
-      _enableOverlay: {
-        type: Boolean,
-        value: false,
-      },
+        _enableOverlay: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * Property for storing references to overlay elements. When the overlays
        * are moved to Gerrit.getRootElement() to be shown they are no-longer
        * children, so they can't be queried along the tree, so they are stored
        * here.
        */
-      _overlays: {
-        type: Object,
-        value: () => ({}),
-      },
-    },
+        _overlays: {
+          type: Object,
+          value: () => ({}),
+        },
+      };
+    }
 
-    observers: [
-      '_commentMessageChanged(comment.message)',
-      '_loadLocalDraft(changeNum, patchNum, comment)',
-      '_isRobotComment(comment)',
-      '_calculateActionstoShow(showActions, isRobotComment)',
-    ],
+    static get observers() {
+      return [
+        '_commentMessageChanged(comment.message)',
+        '_loadLocalDraft(changeNum, patchNum, comment)',
+        '_isRobotComment(comment)',
+        '_calculateActionstoShow(showActions, isRobotComment)',
+      ];
+    }
 
-    behaviors: [
-      Gerrit.FireBehavior,
-      Gerrit.KeyboardShortcutBehavior,
-    ],
-
-    keyBindings: {
-      'ctrl+enter meta+enter ctrl+s meta+s': '_handleSaveKey',
-      'esc': '_handleEsc',
-    },
+    get keyBindings() {
+      return {
+        'ctrl+enter meta+enter ctrl+s meta+s': '_handleSaveKey',
+        'esc': '_handleEsc',
+      };
+    }
 
     attached() {
+      super.attached();
       if (this.editing) {
         this.collapsed = false;
       } else if (this.comment) {
@@ -175,18 +185,19 @@
       this._getIsAdmin().then(isAdmin => {
         this._isAdmin = isAdmin;
       });
-    },
+    }
 
     detached() {
+      super.detached();
       this.cancelDebouncer('fire-update');
       if (this.textarea) {
         this.textarea.closeDropdown();
       }
-    },
+    }
 
     get textarea() {
       return this.$$('#editTextarea');
-    },
+    }
 
     get confirmDeleteOverlay() {
       if (!this._overlays.confirmDelete) {
@@ -195,7 +206,7 @@
         this._overlays.confirmDelete = this.$$('#confirmDeleteOverlay');
       }
       return this._overlays.confirmDelete;
-    },
+    }
 
     get confirmDiscardOverlay() {
       if (!this._overlays.confirmDiscard) {
@@ -204,11 +215,11 @@
         this._overlays.confirmDiscard = this.$$('#confirmDiscardOverlay');
       }
       return this._overlays.confirmDiscard;
-    },
+    }
 
     _computeShowHideIcon(collapsed) {
       return collapsed ? 'gr-icons:expand-more' : 'gr-icons:expand-less';
-    },
+    }
 
     _calculateActionstoShow(showActions, isRobotComment) {
       // Polymer 2: check for undefined
@@ -218,19 +229,19 @@
 
       this._showHumanActions = showActions && !isRobotComment;
       this._showRobotActions = showActions && isRobotComment;
-    },
+    }
 
     _isRobotComment(comment) {
       this.isRobotComment = !!comment.robot_id;
-    },
+    }
 
     isOnParent() {
       return this.side === 'PARENT';
-    },
+    }
 
     _getIsAdmin() {
       return this.$.restAPI.getIsAdmin();
-    },
+    }
 
     /**
      * @param {*=} opt_comment
@@ -273,7 +284,7 @@
       });
 
       return this._xhrPromise;
-    },
+    }
 
     _eraseDraftComment() {
       // Prevents a race condition in which removing the draft comment occurs
@@ -287,7 +298,7 @@
         line: this.comment.line,
         range: this.comment.range,
       });
-    },
+    }
 
     _commentChanged(comment) {
       this.editing = !!comment.__editing;
@@ -295,7 +306,7 @@
       if (this.editing) { // It's a new draft/reply, notify.
         this._fireUpdate();
       }
-    },
+    }
 
     /**
      * @param {!Object=} opt_mixin
@@ -307,21 +318,21 @@
         comment: this.comment,
         patchNum: this.patchNum,
       });
-    },
+    }
 
     _fireSave() {
       this.fire('comment-save', this._getEventPayload());
-    },
+    }
 
     _fireUpdate() {
       this.debounce('fire-update', () => {
         this.fire('comment-update', this._getEventPayload());
       });
-    },
+    }
 
     _draftChanged(draft) {
       this.$.container.classList.toggle('draft', draft);
-    },
+    }
 
     _editingChanged(editing, previousValue) {
       // Polymer 2: observer fires when at least one property is defined.
@@ -346,11 +357,11 @@
           this.textarea.putCursorAtEnd();
         }, 1);
       }
-    },
+    }
 
     _computeDeleteButtonClass(isAdmin, draft) {
       return isAdmin && !draft ? 'showDeleteButtons' : '';
-    },
+    }
 
     _computeSaveDisabled(draft, comment, resolved) {
       // If resolved state has changed and a msg exists, save should be enabled.
@@ -358,7 +369,7 @@
         return false;
       }
       return !draft || draft.trim() === '';
-    },
+    }
 
     _handleSaveKey(e) {
       if (!this._computeSaveDisabled(this._messageText, this.comment,
@@ -366,18 +377,18 @@
         e.preventDefault();
         this._handleSave(e);
       }
-    },
+    }
 
     _handleEsc(e) {
       if (!this._messageText.length) {
         e.preventDefault();
         this._handleCancel(e);
       }
-    },
+    }
 
     _handleToggleCollapsed() {
       this.collapsed = !this.collapsed;
-    },
+    }
 
     _toggleCollapseClass(collapsed) {
       if (collapsed) {
@@ -385,11 +396,11 @@
       } else {
         this.$.container.classList.remove('collapsed');
       }
-    },
+    }
 
     _commentMessageChanged(message) {
       this._messageText = message || '';
-    },
+    }
 
     _messageTextChanged(newValue, oldValue) {
       if (!this.comment || (this.comment && this.comment.id)) {
@@ -414,7 +425,7 @@
           this.$.storage.setDraftComment(commentLocation, message);
         }
       }, STORAGE_DEBOUNCE_INTERVAL);
-    },
+    }
 
     _handleAnchorClick(e) {
       e.preventDefault();
@@ -429,14 +440,14 @@
           side: this.side,
         },
       }));
-    },
+    }
 
     _handleEdit(e) {
       e.preventDefault();
       this._messageText = this.comment.message;
       this.editing = true;
       this.$.reporting.recordDraftInteraction();
-    },
+    }
 
     _handleSave(e) {
       e.preventDefault();
@@ -450,7 +461,7 @@
       const timer = this.$.reporting.getTimer(timingLabel);
       this.set('comment.__editing', false);
       return this.save().then(() => { timer.end(); });
-    },
+    }
 
     _handleCancel(e) {
       e.preventDefault();
@@ -463,12 +474,12 @@
       }
       this._messageText = this.comment.message;
       this.editing = false;
-    },
+    }
 
     _fireDiscard() {
       this.cancelDebouncer('fire-update');
       this.fire('comment-discard', this._getEventPayload());
-    },
+    }
 
     _handleFix() {
       this.dispatchEvent(new CustomEvent('create-fix-comment', {
@@ -476,7 +487,7 @@
         composed: true,
         detail: this._getEventPayload(),
       }));
-    },
+    }
 
     _handleDiscard(e) {
       e.preventDefault();
@@ -491,14 +502,14 @@
         this.confirmDiscardOverlay.querySelector('#confirmDiscardDialog')
             .resetFocus();
       });
-    },
+    }
 
     _handleConfirmDiscard(e) {
       e.preventDefault();
       const timer = this.$.reporting.getTimer(REPORT_DISCARD_DRAFT);
       this._closeConfirmDiscardOverlay();
       return this._discardDraft().then(() => { timer.end(); });
-    },
+    }
 
     _discardDraft() {
       if (!this.comment.__draft) {
@@ -529,11 +540,11 @@
       });
 
       return this._xhrPromise;
-    },
+    }
 
     _closeConfirmDiscardOverlay() {
       this._closeOverlay(this.confirmDiscardOverlay);
-    },
+    }
 
     _getSavingMessage(numPending) {
       if (numPending === 0) {
@@ -544,17 +555,17 @@
         numPending,
         numPending === 1 ? DRAFT_SINGULAR : DRAFT_PLURAL,
       ].join(' ');
-    },
+    }
 
     _showStartRequest() {
       const numPending = ++this._numPendingDraftRequests.number;
       this._updateRequestToast(numPending);
-    },
+    }
 
     _showEndRequest() {
       const numPending = --this._numPendingDraftRequests.number;
       this._updateRequestToast(numPending);
-    },
+    }
 
     _handleFailedDraftRequest() {
       this._numPendingDraftRequests.number--;
@@ -562,7 +573,7 @@
       // Cancel the debouncer so that error toasts from the error-manager will
       // not be overridden.
       this.cancelDebouncer('draft-toast');
-    },
+    }
 
     _updateRequestToast(numPending) {
       const message = this._getSavingMessage(numPending);
@@ -573,7 +584,7 @@
         document.body.dispatchEvent(new CustomEvent(
             'show-alert', {detail: {message}, bubbles: true, composed: true}));
       }, TOAST_DEBOUNCE_INTERVAL);
-    },
+    }
 
     _saveDraft(draft) {
       this._showStartRequest();
@@ -586,7 +597,7 @@
             }
             return result;
           });
-    },
+    }
 
     _deleteDraft(draft) {
       this._showStartRequest();
@@ -599,11 +610,11 @@
         }
         return result;
       });
-    },
+    }
 
     _getPatchNum() {
       return this.isOnParent() ? 'PARENT' : this.patchNum;
-    },
+    }
 
     _loadLocalDraft(changeNum, patchNum, comment) {
       // Polymer 2: check for undefined
@@ -632,7 +643,7 @@
       if (draft) {
         this.set('comment.message', draft.message);
       }
-    },
+    }
 
     _handleToggleResolved() {
       this.$.reporting.recordDraftInteraction();
@@ -646,25 +657,25 @@
         // Save the resolved state immediately.
         this.save(payload.comment);
       }
-    },
+    }
 
     _handleCommentDelete() {
       this._openOverlay(this.confirmDeleteOverlay);
-    },
+    }
 
     _handleCancelDeleteComment() {
       this._closeOverlay(this.confirmDeleteOverlay);
-    },
+    }
 
     _openOverlay(overlay) {
       Polymer.dom(Gerrit.getRootElement()).appendChild(overlay);
       return overlay.open();
-    },
+    }
 
     _closeOverlay(overlay) {
       Polymer.dom(Gerrit.getRootElement()).removeChild(overlay);
       overlay.close();
-    },
+    }
 
     _handleConfirmDeleteComment() {
       const dialog =
@@ -675,6 +686,8 @@
             this._handleCancelDeleteComment();
             this.comment = newComment;
           });
-    },
-  });
+    }
+  }
+
+  customElements.define(GrComment.is, GrComment);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.js b/polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.js
index c2075f0..79cd251 100644
--- a/polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.js
+++ b/polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.js
@@ -17,9 +17,15 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-confirm-delete-comment-dialog',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    */
+  class GrConfirmDeleteCommentDialog extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-confirm-delete-comment-dialog'; }
     /**
      * Fired when the confirm button is pressed.
      *
@@ -32,28 +38,29 @@
      * @event cancel
      */
 
-    properties: {
-      message: String,
-    },
-
-    behaviors: [
-      Gerrit.FireBehavior,
-    ],
+    static get properties() {
+      return {
+        message: String,
+      };
+    }
 
     resetFocus() {
       this.$.messageInput.textarea.focus();
-    },
+    }
 
     _handleConfirmTap(e) {
       e.preventDefault();
       e.stopPropagation();
       this.fire('confirm', {reason: this.message}, {bubbles: false});
-    },
+    }
 
     _handleCancelTap(e) {
       e.preventDefault();
       e.stopPropagation();
       this.fire('cancel', null, {bubbles: false});
-    },
-  });
+    }
+  }
+
+  customElements.define(GrConfirmDeleteCommentDialog.is,
+      GrConfirmDeleteCommentDialog);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.js b/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.js
index 3e87202..6c062f6 100644
--- a/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.js
+++ b/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.js
@@ -19,34 +19,38 @@
 
   const COPY_TIMEOUT_MS = 1000;
 
-  Polymer({
-    is: 'gr-copy-clipboard',
+  class GrCopyClipboard extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-copy-clipboard'; }
 
-    properties: {
-      text: String,
-      buttonTitle: String,
-      hasTooltip: {
-        type: Boolean,
-        value: false,
-      },
-      hideInput: {
-        type: Boolean,
-        value: false,
-      },
-    },
+    static get properties() {
+      return {
+        text: String,
+        buttonTitle: String,
+        hasTooltip: {
+          type: Boolean,
+          value: false,
+        },
+        hideInput: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
 
     focusOnCopy() {
       this.$.button.focus();
-    },
+    }
 
     _computeInputClass(hideInput) {
       return hideInput ? 'hideInput' : '';
-    },
+    }
 
     _handleInputClick(e) {
       e.preventDefault();
       Polymer.dom(e).rootTarget.select();
-    },
+    }
 
     _copyToClipboard() {
       if (this.hideInput) {
@@ -62,6 +66,8 @@
       this.async(
           () => this.$.icon.icon = 'gr-icons:content-copy',
           COPY_TIMEOUT_MS);
-    },
-  });
+    }
+  }
+
+  customElements.define(GrCopyClipboard.is, GrCopyClipboard);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.js b/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.js
index 4e9ff76..4232ef9 100644
--- a/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.js
+++ b/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.js
@@ -22,72 +22,77 @@
     KEEP_VISIBLE: 'keep-visible',
   };
 
-  Polymer({
-    is: 'gr-cursor-manager',
+  class GrCursorManager extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-cursor-manager'; }
 
-    properties: {
-      stops: {
-        type: Array,
-        value() {
-          return [];
+    static get properties() {
+      return {
+        stops: {
+          type: Array,
+          value() {
+            return [];
+          },
+          observer: '_updateIndex',
         },
-        observer: '_updateIndex',
-      },
-      /**
+        /**
        * @type (?Object)
        */
-      target: {
-        type: Object,
-        notify: true,
-        observer: '_scrollToTarget',
-      },
-      /**
+        target: {
+          type: Object,
+          notify: true,
+          observer: '_scrollToTarget',
+        },
+        /**
        * The height of content intended to be included with the target.
        * @type (?number)
        */
-      _targetHeight: Number,
+        _targetHeight: Number,
 
-      /**
+        /**
        * The index of the current target (if any). -1 otherwise.
        */
-      index: {
-        type: Number,
-        value: -1,
-        notify: true,
-      },
+        index: {
+          type: Number,
+          value: -1,
+          notify: true,
+        },
 
-      /**
+        /**
        * The class to apply to the current target. Use null for no class.
        */
-      cursorTargetClass: {
-        type: String,
-        value: null,
-      },
+        cursorTargetClass: {
+          type: String,
+          value: null,
+        },
 
-      /**
+        /**
        * The scroll behavior for the cursor. Values are 'never' and
        * 'keep-visible'. 'keep-visible' will only scroll if the cursor is beyond
        * the viewport.
        * TODO (beckysiegel) figure out why it can be undefined
        * @type (string|undefined)
        */
-      scrollBehavior: {
-        type: String,
-        value: ScrollBehavior.NEVER,
-      },
+        scrollBehavior: {
+          type: String,
+          value: ScrollBehavior.NEVER,
+        },
 
-      /**
+        /**
        * When true, will call element.focus() during scrolling.
        */
-      focusOnMove: {
-        type: Boolean,
-        value: false,
-      },
-    },
+        focusOnMove: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
 
     detached() {
+      super.detached();
       this.unsetCursor();
-    },
+    }
 
     /**
      * Move the cursor forward. Clipped to the ends of the stop list.
@@ -104,11 +109,11 @@
 
     next(opt_condition, opt_getTargetHeight, opt_clipToTop) {
       this._moveCursor(1, opt_condition, opt_getTargetHeight, opt_clipToTop);
-    },
+    }
 
     previous(opt_condition) {
       this._moveCursor(-1, opt_condition);
-    },
+    }
 
     /**
      * Set the cursor to an arbitrary element.
@@ -129,32 +134,32 @@
       this._decorateTarget();
 
       if (opt_noScroll) { this.scrollBehavior = behavior; }
-    },
+    }
 
     unsetCursor() {
       this._unDecorateTarget();
       this.index = -1;
       this.target = null;
       this._targetHeight = null;
-    },
+    }
 
     isAtStart() {
       return this.index === 0;
-    },
+    }
 
     isAtEnd() {
       return this.index === this.stops.length - 1;
-    },
+    }
 
     moveToStart() {
       if (this.stops.length) {
         this.setCursor(this.stops[0]);
       }
-    },
+    }
 
     setCursorAtIndex(index, opt_noScroll) {
       this.setCursor(this.stops[index], opt_noScroll);
-    },
+    }
 
     /**
      * Move the cursor forward or backward by delta. Clipped to the beginning or
@@ -199,19 +204,19 @@
       if (this.focusOnMove) { this.target.focus(); }
 
       this._decorateTarget();
-    },
+    }
 
     _decorateTarget() {
       if (this.target && this.cursorTargetClass) {
         this.target.classList.add(this.cursorTargetClass);
       }
-    },
+    }
 
     _unDecorateTarget() {
       if (this.target && this.cursorTargetClass) {
         this.target.classList.remove(this.cursorTargetClass);
       }
-    },
+    }
 
     /**
      * Get the next stop index indicated by the delta direction.
@@ -247,7 +252,7 @@
       }
 
       return newIndex;
-    },
+    }
 
     _updateIndex() {
       if (!this.target) {
@@ -261,7 +266,7 @@
       } else {
         this.index = newIndex;
       }
-    },
+    }
 
     /**
      * Calculate where the element is relative to the window.
@@ -276,7 +281,7 @@
         top += offsetParent.offsetTop;
       }
       return top;
-    },
+    }
 
     /**
      * @return {boolean}
@@ -286,12 +291,12 @@
       return this.scrollBehavior === ScrollBehavior.KEEP_VISIBLE &&
           top > dims.pageYOffset &&
           top < dims.pageYOffset + dims.innerHeight;
-    },
+    }
 
     _calculateScrollToValue(top, target) {
       const dims = this._getWindowDims();
       return top - (dims.innerHeight / 3) + (target.offsetHeight / 2);
-    },
+    }
 
     _scrollToTarget() {
       if (!this.target || this.scrollBehavior === ScrollBehavior.NEVER) {
@@ -319,7 +324,7 @@
       // element appears to be below the center of the window even when it
       // isn't.
       window.scrollTo(dims.scrollX, scrollToValue);
-    },
+    }
 
     _getWindowDims() {
       return {
@@ -328,6 +333,8 @@
         innerHeight: window.innerHeight,
         pageYOffset: window.pageYOffset,
       };
-    },
-  });
+    }
+  }
+
+  customElements.define(GrCursorManager.is, GrCursorManager);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.js b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.js
index 5b1ef7f..f79c1b6 100644
--- a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.js
+++ b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.js
@@ -31,50 +31,56 @@
     MONTH_DAY_YEAR: 'MMM DD, YYYY', // Aug 29, 1997
   };
 
-  Polymer({
-    is: 'gr-date-formatter',
+  /**
+    * @appliesMixin Gerrit.TooltipMixin
+    */
+  class GrDateFormatter extends Polymer.mixinBehaviors( [
+    Gerrit.TooltipBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-date-formatter'; }
 
-    properties: {
-      dateStr: {
-        type: String,
-        value: null,
-        notify: true,
-      },
-      showDateAndTime: {
-        type: Boolean,
-        value: false,
-      },
+    static get properties() {
+      return {
+        dateStr: {
+          type: String,
+          value: null,
+          notify: true,
+        },
+        showDateAndTime: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * When true, the detailed date appears in a GR-TOOLTIP rather than in the
        * native browser tooltip.
        */
-      hasTooltip: Boolean,
+        hasTooltip: Boolean,
 
-      /**
+        /**
        * The title to be used as the native tooltip or by the tooltip behavior.
        */
-      title: {
-        type: String,
-        reflectToAttribute: true,
-        computed: '_computeFullDateStr(dateStr, _timeFormat)',
-      },
+        title: {
+          type: String,
+          reflectToAttribute: true,
+          computed: '_computeFullDateStr(dateStr, _timeFormat)',
+        },
 
-      _timeFormat: String, // No default value to prevent flickering.
-      _relative: Boolean, // No default value to prevent flickering.
-    },
-
-    behaviors: [
-      Gerrit.TooltipBehavior,
-    ],
+        _timeFormat: String, // No default value to prevent flickering.
+        _relative: Boolean, // No default value to prevent flickering.
+      };
+    }
 
     attached() {
+      super.attached();
       this._loadPreferences();
-    },
+    }
 
     _getUtcOffsetString() {
       return ' UTC' + moment().format('Z');
-    },
+    }
 
     _loadPreferences() {
       return this._getLoggedIn().then(loggedIn => {
@@ -88,7 +94,7 @@
           this._loadRelative(),
         ]);
       });
-    },
+    }
 
     _loadTimeFormat() {
       return this._getPreferences().then(preferences => {
@@ -104,22 +110,22 @@
             throw Error('Invalid time format: ' + timeFormat);
         }
       });
-    },
+    }
 
     _loadRelative() {
       return this._getPreferences().then(prefs => {
         // prefs.relative_date_in_change_table is not set when false.
         this._relative = !!(prefs && prefs.relative_date_in_change_table);
       });
-    },
+    }
 
     _getLoggedIn() {
       return this.$.restAPI.getLoggedIn();
-    },
+    }
 
     _getPreferences() {
       return this.$.restAPI.getPreferences();
-    },
+    }
 
     /**
      * Return true if date is within 24 hours and on the same day.
@@ -127,7 +133,7 @@
     _isWithinDay(now, date) {
       const diff = -date.diff(now);
       return diff < Duration.DAY && date.day() === now.getDay();
-    },
+    }
 
     /**
      * Returns true if date is from one to six months.
@@ -136,7 +142,7 @@
       const diff = -date.diff(now);
       return (date.day() !== now.getDay() || diff >= Duration.DAY) &&
           diff < 180 * Duration.DAY;
-    },
+    }
 
     _computeDateStr(dateStr, timeFormat, relative, showDateAndTime) {
       if (!dateStr) { return ''; }
@@ -163,13 +169,13 @@
         }
       }
       return date.format(format);
-    },
+    }
 
     _timeToSecondsFormat(timeFormat) {
       return timeFormat === TimeFormats.TIME_12 ?
         TimeFormats.TIME_12_WITH_SEC :
         TimeFormats.TIME_24_WITH_SEC;
-    },
+    }
 
     _computeFullDateStr(dateStr, timeFormat) {
       // Polymer 2: check for undefined
@@ -186,6 +192,8 @@
       let format = TimeFormats.MONTH_DAY_YEAR + ', ';
       format += this._timeToSecondsFormat(timeFormat);
       return date.format(format) + this._getUtcOffsetString();
-    },
-  });
+    }
+  }
+
+  customElements.define(GrDateFormatter.is, GrDateFormatter);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-dialog/gr-dialog.js b/polygerrit-ui/app/elements/shared/gr-dialog/gr-dialog.js
index 68dc537..b84434e 100644
--- a/polygerrit-ui/app/elements/shared/gr-dialog/gr-dialog.js
+++ b/polygerrit-ui/app/elements/shared/gr-dialog/gr-dialog.js
@@ -17,9 +17,15 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-dialog',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    */
+  class GrDialog extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-dialog'; }
     /**
      * Fired when the confirm button is pressed.
      *
@@ -32,33 +38,32 @@
      * @event cancel
      */
 
-    properties: {
-      confirmLabel: {
-        type: String,
-        value: 'Confirm',
-      },
-      // Supplying an empty cancel label will hide the button completely.
-      cancelLabel: {
-        type: String,
-        value: 'Cancel',
-      },
-      disabled: {
-        type: Boolean,
-        value: false,
-      },
-      confirmOnEnter: {
-        type: Boolean,
-        value: false,
-      },
-    },
+    static get properties() {
+      return {
+        confirmLabel: {
+          type: String,
+          value: 'Confirm',
+        },
+        // Supplying an empty cancel label will hide the button completely.
+        cancelLabel: {
+          type: String,
+          value: 'Cancel',
+        },
+        disabled: {
+          type: Boolean,
+          value: false,
+        },
+        confirmOnEnter: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
 
-    behaviors: [
-      Gerrit.FireBehavior,
-    ],
-
-    hostAttributes: {
-      role: 'dialog',
-    },
+    ready() {
+      super.ready();
+      this._ensureAttribute('role', 'dialog');
+    }
 
     _handleConfirm(e) {
       if (this.disabled) { return; }
@@ -66,24 +71,26 @@
       e.preventDefault();
       e.stopPropagation();
       this.fire('confirm', null, {bubbles: false});
-    },
+    }
 
     _handleCancelTap(e) {
       e.preventDefault();
       e.stopPropagation();
       this.fire('cancel', null, {bubbles: false});
-    },
+    }
 
     _handleKeydown(e) {
       if (this.confirmOnEnter && e.keyCode === 13) { this._handleConfirm(e); }
-    },
+    }
 
     resetFocus() {
       this.$.confirm.focus();
-    },
+    }
 
     _computeCancelClass(cancelLabel) {
       return cancelLabel.length ? '' : 'hidden';
-    },
-  });
+    }
+  }
+
+  customElements.define(GrDialog.is, GrDialog);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.js b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.js
index 36fdf5b..6e34bbc 100644
--- a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.js
+++ b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.js
@@ -17,62 +17,68 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-diff-preferences',
+  class GrDiffPreferences extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-diff-preferences'; }
 
-    properties: {
-      hasUnsavedChanges: {
-        type: Boolean,
-        notify: true,
-        value: false,
-      },
+    static get properties() {
+      return {
+        hasUnsavedChanges: {
+          type: Boolean,
+          notify: true,
+          value: false,
+        },
 
-      /** @type {?} */
-      diffPrefs: Object,
-    },
+        /** @type {?} */
+        diffPrefs: Object,
+      };
+    }
 
     loadData() {
       return this.$.restAPI.getDiffPreferences().then(prefs => {
         this.diffPrefs = prefs;
       });
-    },
+    }
 
     _handleDiffPrefsChanged() {
       this.hasUnsavedChanges = true;
-    },
+    }
 
     _handleLineWrappingTap() {
       this.set('diffPrefs.line_wrapping', this.$.lineWrappingInput.checked);
       this._handleDiffPrefsChanged();
-    },
+    }
 
     _handleShowTabsTap() {
       this.set('diffPrefs.show_tabs', this.$.showTabsInput.checked);
       this._handleDiffPrefsChanged();
-    },
+    }
 
     _handleShowTrailingWhitespaceTap() {
       this.set('diffPrefs.show_whitespace_errors',
           this.$.showTrailingWhitespaceInput.checked);
       this._handleDiffPrefsChanged();
-    },
+    }
 
     _handleSyntaxHighlightTap() {
       this.set('diffPrefs.syntax_highlighting',
           this.$.syntaxHighlightInput.checked);
       this._handleDiffPrefsChanged();
-    },
+    }
 
     _handleAutomaticReviewTap() {
       this.set('diffPrefs.manual_review',
           !this.$.automaticReviewInput.checked);
       this._handleDiffPrefsChanged();
-    },
+    }
 
     save() {
       return this.$.restAPI.saveDiffPreferences(this.diffPrefs).then(res => {
         this.hasUnsavedChanges = false;
       });
-    },
-  });
+    }
+  }
+
+  customElements.define(GrDiffPreferences.is, GrDiffPreferences);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.js b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.js
index 121aa35..8ee4820 100644
--- a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.js
+++ b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.js
@@ -17,40 +17,46 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-download-commands',
+  /**
+    * @appliesMixin Gerrit.RESTClientMixin
+    */
+  class GrDownloadCommands extends Polymer.mixinBehaviors( [
+    Gerrit.RESTClientBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-download-commands'; }
 
-    properties: {
-      commands: Array,
-      _loggedIn: {
-        type: Boolean,
-        value: false,
-        observer: '_loggedInChanged',
-      },
-      schemes: Array,
-      selectedScheme: {
-        type: String,
-        notify: true,
-      },
-    },
-
-    behaviors: [
-      Gerrit.RESTClientBehavior,
-    ],
+    static get properties() {
+      return {
+        commands: Array,
+        _loggedIn: {
+          type: Boolean,
+          value: false,
+          observer: '_loggedInChanged',
+        },
+        schemes: Array,
+        selectedScheme: {
+          type: String,
+          notify: true,
+        },
+      };
+    }
 
     attached() {
+      super.attached();
       this._getLoggedIn().then(loggedIn => {
         this._loggedIn = loggedIn;
       });
-    },
+    }
 
     focusOnCopy() {
       this.$$('gr-shell-command').focusOnCopy();
-    },
+    }
 
     _getLoggedIn() {
       return this.$.restAPI.getLoggedIn();
-    },
+    }
 
     _loggedInChanged(loggedIn) {
       if (!loggedIn) { return; }
@@ -60,7 +66,7 @@
           this.selectedScheme = prefs.download_scheme.toLowerCase();
         }
       });
-    },
+    }
 
     _handleTabChange(e) {
       const scheme = this.schemes[e.detail.value];
@@ -71,15 +77,17 @@
               {download_scheme: this.selectedScheme});
         }
       }
-    },
+    }
 
     _computeSelected(schemes, selectedScheme) {
       return (schemes.findIndex(scheme => scheme === selectedScheme) || 0)
           + '';
-    },
+    }
 
     _computeShowTabs(schemes) {
       return schemes.length > 1 ? '' : 'hidden';
-    },
-  });
+    }
+  }
+
+  customElements.define(GrDownloadCommands.is, GrDownloadCommands);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.js b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.js
index 1f0d01c..2197733 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.js
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.js
@@ -45,9 +45,10 @@
    */
   Defs.item;
 
-  Polymer({
-    is: 'gr-dropdown-list',
-
+  class GrDropdownList extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-dropdown-list'; }
     /**
      * Fired when the selected value changes
      *
@@ -56,24 +57,28 @@
      * @property {string|number} value
      */
 
-    properties: {
-      initialCount: Number,
-      /** @type {!Array<!Defs.item>} */
-      items: Object,
-      text: String,
-      disabled: {
-        type: Boolean,
-        value: false,
-      },
-      value: {
-        type: String,
-        notify: true,
-      },
-    },
+    static get properties() {
+      return {
+        initialCount: Number,
+        /** @type {!Array<!Defs.item>} */
+        items: Object,
+        text: String,
+        disabled: {
+          type: Boolean,
+          value: false,
+        },
+        value: {
+          type: String,
+          notify: true,
+        },
+      };
+    }
 
-    observers: [
-      '_handleValueChange(value, items)',
-    ],
+    static get observers() {
+      return [
+        '_handleValueChange(value, items)',
+      ];
+    }
 
     /**
      * Handle a click on the iron-dropdown element.
@@ -85,7 +90,7 @@
       this.async(() => {
         this.$.dropdown.close();
       }, 1);
-    },
+    }
 
     /**
      * Handle a click on the button to open the dropdown.
@@ -93,18 +98,18 @@
      */
     _showDropdownTapHandler(e) {
       this._open();
-    },
+    }
 
     /**
      * Open the dropdown.
      */
     _open() {
       this.$.dropdown.open();
-    },
+    }
 
     _computeMobileText(item) {
       return item.mobileText ? item.mobileText : item.text;
-    },
+    }
 
     _handleValueChange(value, items) {
       // Polymer 2: check for undefined
@@ -123,6 +128,8 @@
         detail: {value},
         bubbles: false,
       }));
-    },
-  });
+    }
+  }
+
+  customElements.define(GrDropdownList.is, GrDropdownList);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js
index 7273268..9725f0c 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js
@@ -20,9 +20,17 @@
   const REL_NOOPENER = 'noopener';
   const REL_EXTERNAL = 'external';
 
-  Polymer({
-    is: 'gr-dropdown',
-
+  /**
+    * @appliesMixin Gerrit.BaseUrlMixin
+    * @appliesMixin Gerrit.KeyboardShortcutMixin
+    */
+  class GrDropdown extends Polymer.mixinBehaviors( [
+    Gerrit.BaseUrlBehavior,
+    Gerrit.KeyboardShortcutBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-dropdown'; }
     /**
      * Fired when a non-link dropdown item with the given ID is tapped.
      *
@@ -35,60 +43,59 @@
      * @event tap-item
      */
 
-    properties: {
-      items: {
-        type: Array,
-        observer: '_resetCursorStops',
-      },
-      downArrow: Boolean,
-      topContent: Object,
-      horizontalAlign: {
-        type: String,
-        value: 'left',
-      },
+    static get properties() {
+      return {
+        items: {
+          type: Array,
+          observer: '_resetCursorStops',
+        },
+        downArrow: Boolean,
+        topContent: Object,
+        horizontalAlign: {
+          type: String,
+          value: 'left',
+        },
 
-      /**
+        /**
        * Style the dropdown trigger as a link (rather than a button).
        */
-      link: {
-        type: Boolean,
-        value: false,
-      },
+        link: {
+          type: Boolean,
+          value: false,
+        },
 
-      verticalOffset: {
-        type: Number,
-        value: 40,
-      },
+        verticalOffset: {
+          type: Number,
+          value: 40,
+        },
 
-      /**
+        /**
        * List the IDs of dropdown buttons to be disabled. (Note this only
        * diisables bittons and not link entries.)
        */
-      disabledIds: {
-        type: Array,
-        value() { return []; },
-      },
+        disabledIds: {
+          type: Array,
+          value() { return []; },
+        },
 
-      /**
+        /**
        * The elements of the list.
        */
-      _listElements: {
-        type: Array,
-        value() { return []; },
-      },
-    },
+        _listElements: {
+          type: Array,
+          value() { return []; },
+        },
+      };
+    }
 
-    behaviors: [
-      Gerrit.BaseUrlBehavior,
-      Gerrit.KeyboardShortcutBehavior,
-    ],
-
-    keyBindings: {
-      'down': '_handleDown',
-      'enter space': '_handleEnter',
-      'tab': '_handleTab',
-      'up': '_handleUp',
-    },
+    get keyBindings() {
+      return {
+        'down': '_handleDown',
+        'enter space': '_handleEnter',
+        'tab': '_handleTab',
+        'up': '_handleUp',
+      };
+    }
 
     /**
      * Handle the up key.
@@ -102,7 +109,7 @@
       } else {
         this._open();
       }
-    },
+    }
 
     /**
      * Handle the down key.
@@ -116,7 +123,7 @@
       } else {
         this._open();
       }
-    },
+    }
 
     /**
      * Handle the tab key.
@@ -128,7 +135,7 @@
         e.preventDefault();
         e.stopPropagation();
       }
-    },
+    }
 
     /**
      * Handle the enter key.
@@ -146,7 +153,7 @@
       } else {
         this._open();
       }
-    },
+    }
 
     /**
      * Handle a click on the iron-dropdown element.
@@ -154,7 +161,7 @@
      */
     _handleDropdownTap(e) {
       this._close();
-    },
+    }
 
     /**
      * Hanlde a click on the button to open the dropdown.
@@ -168,7 +175,7 @@
       } else {
         this._open();
       }
-    },
+    }
 
     /**
      * Open the dropdown and initialize the cursor.
@@ -178,7 +185,7 @@
       this._resetCursorStops();
       this.$.cursor.setCursorAtIndex(0);
       this.$.cursor.target.focus();
-    },
+    }
 
     _close() {
       // async is needed so that that the click event is fired before the
@@ -186,7 +193,7 @@
       this.async(() => {
         this.$.dropdown.close();
       }, 1);
-    },
+    }
 
     /**
      * Get the class for a top-content item based on the given boolean.
@@ -195,7 +202,7 @@
      */
     _getClassIfBold(bold) {
       return bold ? 'bold-text' : '';
-    },
+    }
 
     /**
      * Build a URL for the given host and path. The base URL will be only added,
@@ -208,7 +215,7 @@
       const base = path.startsWith(this.getBaseUrl()) ?
         '' : this.getBaseUrl();
       return '//' + host + base + path;
-    },
+    }
 
     /**
      * Build a scheme-relative URL for the current host. Will include the base
@@ -220,7 +227,7 @@
     _computeRelativeURL(path) {
       const host = window.location.host;
       return this._computeURLHelper(host, path);
-    },
+    }
 
     /**
      * Compute the URL for a link object.
@@ -235,7 +242,7 @@
         return link.url;
       }
       return this._computeRelativeURL(link.url);
-    },
+    }
 
     /**
      * Compute the value for the rel attribute of an anchor for the given link
@@ -249,7 +256,7 @@
       if (link.target) { return REL_NOOPENER; }
       if (link.external) { return REL_EXTERNAL; }
       return null;
-    },
+    }
 
     /**
      * Handle a click on an item of the dropdown.
@@ -264,7 +271,7 @@
         }
         this.dispatchEvent(new CustomEvent('tap-item-' + id));
       }
-    },
+    }
 
     /**
      * If a dropdown item is shown as a button, get the class for the button.
@@ -275,7 +282,7 @@
      */
     _computeDisabledClass(id, disabledIdsRecord) {
       return disabledIdsRecord.base.includes(id) ? 'disabled' : '';
-    },
+    }
 
     /**
      * Recompute the stops for the dropdown item cursor.
@@ -286,14 +293,16 @@
         this._listElements = Array.from(
             Polymer.dom(this.root).querySelectorAll('li'));
       }
-    },
+    }
 
     _computeHasTooltip(tooltip) {
       return !!tooltip;
-    },
+    }
 
     _computeIsDownload(link) {
       return !!link.download;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrDropdown.is, GrDropdown);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-editable-content/gr-editable-content.js b/polygerrit-ui/app/elements/shared/gr-editable-content/gr-editable-content.js
index 75c0201..49b1025 100644
--- a/polygerrit-ui/app/elements/shared/gr-editable-content/gr-editable-content.js
+++ b/polygerrit-ui/app/elements/shared/gr-editable-content/gr-editable-content.js
@@ -20,9 +20,15 @@
   const RESTORED_MESSAGE = 'Content restored from a previous edit.';
   const STORAGE_DEBOUNCE_INTERVAL_MS = 400;
 
-  Polymer({
-    is: 'gr-editable-content',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    */
+  class GrEditableContent extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-editable-content'; }
     /**
      * Fired when the save button is pressed.
      *
@@ -41,42 +47,40 @@
      * @event show-alert
      */
 
-    properties: {
-      content: {
-        notify: true,
-        type: String,
-      },
-      disabled: {
-        reflectToAttribute: true,
-        type: Boolean,
-        value: false,
-      },
-      editing: {
-        observer: '_editingChanged',
-        type: Boolean,
-        value: false,
-      },
-      removeZeroWidthSpace: Boolean,
-      // If no storage key is provided, content is not stored.
-      storageKey: String,
-      _saveDisabled: {
-        computed: '_computeSaveDisabled(disabled, content, _newContent)',
-        type: Boolean,
-        value: true,
-      },
-      _newContent: {
-        type: String,
-        observer: '_newContentChanged',
-      },
-    },
-
-    behaviors: [
-      Gerrit.FireBehavior,
-    ],
+    static get properties() {
+      return {
+        content: {
+          notify: true,
+          type: String,
+        },
+        disabled: {
+          reflectToAttribute: true,
+          type: Boolean,
+          value: false,
+        },
+        editing: {
+          observer: '_editingChanged',
+          type: Boolean,
+          value: false,
+        },
+        removeZeroWidthSpace: Boolean,
+        // If no storage key is provided, content is not stored.
+        storageKey: String,
+        _saveDisabled: {
+          computed: '_computeSaveDisabled(disabled, content, _newContent)',
+          type: Boolean,
+          value: true,
+        },
+        _newContent: {
+          type: String,
+          observer: '_newContentChanged',
+        },
+      };
+    }
 
     focusTextarea() {
       this.$$('iron-autogrow-textarea').textarea.focus();
-    },
+    }
 
     _newContentChanged(newContent, oldContent) {
       if (!this.storageKey) { return; }
@@ -88,7 +92,7 @@
           this.$.storage.eraseEditableContentItem(this.storageKey);
         }
       }, STORAGE_DEBOUNCE_INTERVAL_MS);
-    },
+    }
 
     _editingChanged(editing) {
       if (!editing) { return; }
@@ -114,7 +118,7 @@
       this._newContent = this.removeZeroWidthSpace ?
         content.replace(/^R=\u200B/gm, 'R=') :
         content;
-    },
+    }
 
     _computeSaveDisabled(disabled, content, newContent) {
       // Polymer 2: check for undefined
@@ -127,17 +131,19 @@
       }
 
       return disabled || (content === newContent);
-    },
+    }
 
     _handleSave(e) {
       e.preventDefault();
       this.fire('editable-content-save', {content: this._newContent});
-    },
+    }
 
     _handleCancel(e) {
       e.preventDefault();
       this.editing = false;
       this.fire('editable-content-cancel');
-    },
-  });
+    }
+  }
+
+  customElements.define(GrEditableContent.is, GrEditableContent);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label.js b/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label.js
index 4485551..b989401 100644
--- a/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label.js
+++ b/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label.js
@@ -20,76 +20,84 @@
   const AWAIT_MAX_ITERS = 10;
   const AWAIT_STEP = 5;
 
-  Polymer({
-    is: 'gr-editable-label',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    * @appliesMixin Gerrit.KeyboardShortcutMixin
+    */
+  class GrEditableLabel extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+    Gerrit.KeyboardShortcutBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-editable-label'; }
     /**
      * Fired when the value is changed.
      *
      * @event changed
      */
 
-    properties: {
-      labelText: String,
-      editing: {
-        type: Boolean,
-        value: false,
-      },
-      value: {
-        type: String,
-        notify: true,
-        value: '',
-        observer: '_updateTitle',
-      },
-      placeholder: {
-        type: String,
-        value: '',
-      },
-      readOnly: {
-        type: Boolean,
-        value: false,
-      },
-      uppercase: {
-        type: Boolean,
-        reflectToAttribute: true,
-        value: false,
-      },
-      maxLength: Number,
-      _inputText: String,
-      // This is used to push the iron-input element up on the page, so
-      // the input is placed in approximately the same position as the
-      // trigger.
-      _verticalOffset: {
-        type: Number,
-        readOnly: true,
-        value: -30,
-      },
-    },
+    static get properties() {
+      return {
+        labelText: String,
+        editing: {
+          type: Boolean,
+          value: false,
+        },
+        value: {
+          type: String,
+          notify: true,
+          value: '',
+          observer: '_updateTitle',
+        },
+        placeholder: {
+          type: String,
+          value: '',
+        },
+        readOnly: {
+          type: Boolean,
+          value: false,
+        },
+        uppercase: {
+          type: Boolean,
+          reflectToAttribute: true,
+          value: false,
+        },
+        maxLength: Number,
+        _inputText: String,
+        // This is used to push the iron-input element up on the page, so
+        // the input is placed in approximately the same position as the
+        // trigger.
+        _verticalOffset: {
+          type: Number,
+          readOnly: true,
+          value: -30,
+        },
+      };
+    }
 
-    behaviors: [
-      Gerrit.FireBehavior,
-      Gerrit.KeyboardShortcutBehavior,
-    ],
+    ready() {
+      super.ready();
+      this._ensureAttribute('tabindex', '0');
+    }
 
-    keyBindings: {
-      enter: '_handleEnter',
-      esc: '_handleEsc',
-    },
-
-    hostAttributes: {
-      tabindex: '0',
-    },
+    get keyBindings() {
+      return {
+        enter: '_handleEnter',
+        esc: '_handleEsc',
+      };
+    }
 
     _usePlaceholder(value, placeholder) {
       return (!value || !value.length) && placeholder;
-    },
+    }
 
     _computeLabel(value, placeholder) {
       if (this._usePlaceholder(value, placeholder)) {
         return placeholder;
       }
       return value;
-    },
+    }
 
     _showDropdown() {
       if (this.readOnly || this.editing) { return; }
@@ -98,13 +106,13 @@
         if (!this.$.input.value) { return; }
         this._nativeInput.setSelectionRange(0, this.$.input.value.length);
       });
-    },
+    }
 
     open() {
       return this._open().then(() => {
         this._nativeInput.focus();
       });
-    },
+    }
 
     _open(...args) {
       this.$.dropdown.open();
@@ -115,7 +123,7 @@
         Polymer.IronOverlayBehaviorImpl.open.apply(this.$.dropdown, args);
         this._awaitOpen(resolve);
       });
-    },
+    }
 
     /**
      * NOTE: (wyatta) Slightly hacky way to listen to the overlay actually
@@ -133,11 +141,11 @@
         }, AWAIT_STEP);
       };
       step.call(this);
-    },
+    }
 
     _id() {
       return this.getAttribute('id') || 'global';
-    },
+    }
 
     _save() {
       if (!this.editing) { return; }
@@ -145,20 +153,20 @@
       this.value = this._inputText;
       this.editing = false;
       this.fire('changed', this.value);
-    },
+    }
 
     _cancel() {
       if (!this.editing) { return; }
       this.$.dropdown.close();
       this.editing = false;
       this._inputText = this.value;
-    },
+    }
 
     get _nativeInput() {
       // In Polymer 2, the namespace of nativeInput
       // changed from input to nativeInput
       return this.$.input.$.nativeInput || this.$.input.$.input;
-    },
+    }
 
     _handleEnter(e) {
       e = this.getKeyboardEvent(e);
@@ -167,7 +175,7 @@
         e.preventDefault();
         this._save();
       }
-    },
+    }
 
     _handleEsc(e) {
       e = this.getKeyboardEvent(e);
@@ -176,7 +184,7 @@
         e.preventDefault();
         this._cancel();
       }
-    },
+    }
 
     _computeLabelClass(readOnly, value, placeholder) {
       const classes = [];
@@ -185,10 +193,12 @@
         classes.push('placeholder');
       }
       return classes.join(' ');
-    },
+    }
 
     _updateTitle(value) {
       this.setAttribute('title', this._computeLabel(value, this.placeholder));
-    },
-  });
+    }
+  }
+
+  customElements.define(GrEditableLabel.is, GrEditableLabel);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-fixed-panel/gr-fixed-panel.js b/polygerrit-ui/app/elements/shared/gr-fixed-panel/gr-fixed-panel.js
index 2c32709..af533bc 100644
--- a/polygerrit-ui/app/elements/shared/gr-fixed-panel/gr-fixed-panel.js
+++ b/polygerrit-ui/app/elements/shared/gr-fixed-panel/gr-fixed-panel.js
@@ -17,47 +17,52 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-fixed-panel',
+  class GrFixedPanel extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-fixed-panel'; }
 
-    properties: {
-      floatingDisabled: Boolean,
-      readyForMeasure: {
-        type: Boolean,
-        observer: '_readyForMeasureObserver',
-      },
-      keepOnScroll: {
-        type: Boolean,
-        value: false,
-      },
-      _isMeasured: {
-        type: Boolean,
-        value: false,
-      },
+    static get properties() {
+      return {
+        floatingDisabled: Boolean,
+        readyForMeasure: {
+          type: Boolean,
+          observer: '_readyForMeasureObserver',
+        },
+        keepOnScroll: {
+          type: Boolean,
+          value: false,
+        },
+        _isMeasured: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * Initial offset from the top of the document, in pixels.
        */
-      _topInitial: Number,
+        _topInitial: Number,
 
-      /**
+        /**
        * Current offset from the top of the window, in pixels.
        */
-      _topLast: Number,
+        _topLast: Number,
 
-      _headerHeight: Number,
-      _headerFloating: {
-        type: Boolean,
-        value: false,
-      },
-      _observer: {
-        type: Object,
-        value: null,
-      },
-      _webComponentsReady: Boolean,
-    },
+        _headerHeight: Number,
+        _headerFloating: {
+          type: Boolean,
+          value: false,
+        },
+        _observer: {
+          type: Object,
+          value: null,
+        },
+        _webComponentsReady: Boolean,
+      };
+    }
 
     attached() {
+      super.attached();
       if (this.floatingDisabled) {
         return;
       }
@@ -69,21 +74,22 @@
       this.listen(window, 'scroll', '_updateOnScroll');
       this._observer = new MutationObserver(this.update.bind(this));
       this._observer.observe(this.$.header, {childList: true, subtree: true});
-    },
+    }
 
     detached() {
+      super.detached();
       this.unlisten(window, 'scroll', '_updateOnScroll');
       this.unlisten(window, 'resize', 'update');
       if (this._observer) {
         this._observer.disconnect();
       }
-    },
+    }
 
     _readyForMeasureObserver(readyForMeasure) {
       if (readyForMeasure) {
         this.update();
       }
-    },
+    }
 
     _computeHeaderClass(headerFloating, topLast) {
       const fixedAtTop = this.keepOnScroll && topLast === 0;
@@ -91,7 +97,7 @@
         headerFloating ? 'floating' : '',
         fixedAtTop ? 'fixedAtTop' : '',
       ].join(' ');
-    },
+    }
 
     unfloat() {
       if (this.floatingDisabled) {
@@ -100,19 +106,19 @@
       this.$.header.style.top = '';
       this._headerFloating = false;
       this.updateStyles({'--header-height': ''});
-    },
+    }
 
     update() {
       this.debounce('update', () => {
         this._updateDebounced();
       }, 100);
-    },
+    }
 
     _updateOnScroll() {
       this.debounce('update', () => {
         this._updateDebounced();
       });
-    },
+    }
 
     _updateDebounced() {
       if (this.floatingDisabled) {
@@ -121,11 +127,11 @@
       this._isMeasured = false;
       this._maybeFloatHeader();
       this._reposition();
-    },
+    }
 
     _getElementTop() {
       return this.getBoundingClientRect().top;
-    },
+    }
 
     _reposition() {
       if (!this._headerFloating) {
@@ -155,7 +161,7 @@
         }
         this._topLast = newTop;
       }
-    },
+    }
 
     _measure() {
       if (this._isMeasured) {
@@ -171,12 +177,12 @@
       this._topInitial =
         this.getBoundingClientRect().top + document.body.scrollTop;
       this._isMeasured = true;
-    },
+    }
 
     _isFloatingNeeded() {
       return this.keepOnScroll ||
         document.body.scrollWidth > document.body.clientWidth;
-    },
+    }
 
     _maybeFloatHeader() {
       if (!this._isFloatingNeeded()) {
@@ -186,11 +192,13 @@
       if (this._isMeasured) {
         this._floatHeader();
       }
-    },
+    }
 
     _floatHeader() {
       this.updateStyles({'--header-height': this._headerHeight + 'px'});
       this._headerFloating = true;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrFixedPanel.is, GrFixedPanel);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text.js b/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text.js
index 4e68d42..7730a75 100644
--- a/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text.js
+++ b/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text.js
@@ -20,30 +20,37 @@
   // eslint-disable-next-line no-unused-vars
   const QUOTE_MARKER_PATTERN = /\n\s?>\s/g;
 
-  Polymer({
-    is: 'gr-formatted-text',
+  class GrFormattedText extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-formatted-text'; }
 
-    properties: {
-      content: {
-        type: String,
-        observer: '_contentChanged',
-      },
-      config: Object,
-      noTrailingMargin: {
-        type: Boolean,
-        value: false,
-      },
-    },
+    static get properties() {
+      return {
+        content: {
+          type: String,
+          observer: '_contentChanged',
+        },
+        config: Object,
+        noTrailingMargin: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
 
-    observers: [
-      '_contentOrConfigChanged(content, config)',
-    ],
+    static get observers() {
+      return [
+        '_contentOrConfigChanged(content, config)',
+      ];
+    }
 
     ready() {
+      super.ready();
       if (this.noTrailingMargin) {
         this.classList.add('noTrailingMargin');
       }
-    },
+    }
 
     /**
      * Get the plain text as it appears in the generated DOM.
@@ -56,7 +63,7 @@
      */
     getTextContent() {
       return this._blocksToText(this._computeBlocks(this.content));
-    },
+    }
 
     _contentChanged(content) {
       // In the case where the config may not be set (perhaps due to the
@@ -64,7 +71,7 @@
       // prevent waiting on the config to display the text.
       if (this.config) { return; }
       this._contentOrConfigChanged(content);
-    },
+    }
 
     /**
      * Given a source string, update the DOM inside #container.
@@ -81,7 +88,7 @@
       for (const node of this._computeNodes(this._computeBlocks(content))) {
         container.appendChild(node);
       }
-    },
+    }
 
     /**
      * Given a source string, parse into an array of block objects. Each block
@@ -127,7 +134,7 @@
         }
       }
       return result;
-    },
+    }
 
     /**
      * Take a block of comment text that contains a list and potentially
@@ -201,7 +208,7 @@
       if (block !== null) {
         out.push(block);
       }
-    },
+    }
 
     _makeQuote(p) {
       const quotedLines = p
@@ -212,21 +219,21 @@
         type: 'quote',
         blocks: this._computeBlocks(quotedLines),
       };
-    },
+    }
 
     _isQuote(p) {
       return p.startsWith('> ') || p.startsWith(' > ');
-    },
+    }
 
     _isPreFormat(p) {
       return p.includes('\n ') || p.includes('\n\t') ||
           p.startsWith(' ') || p.startsWith('\t');
-    },
+    }
 
     _isList(p) {
       return p.includes('\n- ') || p.includes('\n* ') ||
           p.startsWith('- ') || p.startsWith('* ');
-    },
+    }
 
     /**
      * @param {string} content
@@ -241,7 +248,7 @@
         text.classList.add('pre');
       }
       return text;
-    },
+    }
 
     /**
      * Map an array of block objects to an array of DOM nodes.
@@ -278,7 +285,7 @@
           return ul;
         }
       });
-    },
+    }
 
     _blocksToText(blocks) {
       return blocks.map(block => {
@@ -292,6 +299,8 @@
           return block.items.join('\n');
         }
       }).join('\n\n');
-    },
-  });
+    }
+  }
+
+  customElements.define(GrFormattedText.is, GrFormattedText);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard.js b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard.js
index 3a43191..5e3cfb3 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard.js
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard.js
@@ -25,82 +25,90 @@
    */
   const DIAGONAL_OVERFLOW = 15;
 
-  Polymer({
-    is: 'gr-hovercard',
+  class GrHovercard extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-hovercard'; }
 
-    properties: {
+    static get properties() {
+      return {
       /**
        * @type {?}
        */
-      _target: Object,
+        _target: Object,
 
-      /**
+        /**
        * Determines whether or not the hovercard is visible.
        *
        * @type {boolean}
        */
-      _isShowing: {
-        type: Boolean,
-        value: false,
-      },
-      /**
+        _isShowing: {
+          type: Boolean,
+          value: false,
+        },
+        /**
        * The `id` of the element that the hovercard is anchored to.
        *
        * @type {string}
        */
-      for: {
-        type: String,
-        observer: '_forChanged',
-      },
+        for: {
+          type: String,
+          observer: '_forChanged',
+        },
 
-      /**
+        /**
        * The spacing between the top of the hovercard and the element it is
        * anchored to.
        *
        * @type {number}
        */
-      offset: {
-        type: Number,
-        value: 14,
-      },
+        offset: {
+          type: Number,
+          value: 14,
+        },
 
-      /**
+        /**
        * Positions the hovercard to the top, right, bottom, left, bottom-left,
        * bottom-right, top-left, or top-right of its content.
        *
        * @type {string}
        */
-      position: {
-        type: String,
-        value: 'bottom',
-      },
+        position: {
+          type: String,
+          value: 'bottom',
+        },
 
-      container: Object,
-      /**
+        container: Object,
+        /**
        * ID for the container element.
        *
        * @type {string}
        */
-      containerId: {
-        type: String,
-        value: 'gr-hovercard-container',
-      },
-    },
-
-    listeners: {
-      mouseleave: 'hide',
-    },
+        containerId: {
+          type: String,
+          value: 'gr-hovercard-container',
+        },
+      };
+    }
 
     attached() {
+      super.attached();
       if (!this._target) { this._target = this.target; }
       this.listen(this._target, 'mouseenter', 'show');
       this.listen(this._target, 'focus', 'show');
       this.listen(this._target, 'mouseleave', 'hide');
       this.listen(this._target, 'blur', 'hide');
       this.listen(this._target, 'click', 'hide');
-    },
+    }
+
+    created() {
+      super.created();
+      this.addEventListener('mouseleave',
+          e => this.hide(e));
+    }
 
     ready() {
+      super.ready();
       // First, check to see if the container has already been created.
       this.container = Gerrit.getRootElement()
           .querySelector('#' + this.containerId);
@@ -111,7 +119,7 @@
       this.container = document.createElement('div');
       this.container.setAttribute('id', this.containerId);
       Gerrit.getRootElement().appendChild(this.container);
-    },
+    }
 
     removeListeners() {
       this.unlisten(this._target, 'mouseenter', 'show');
@@ -119,7 +127,7 @@
       this.unlisten(this._target, 'mouseleave', 'hide');
       this.unlisten(this._target, 'blur', 'hide');
       this.unlisten(this._target, 'click', 'hide');
-    },
+    }
 
     /**
      * Returns the target element that the hovercard is anchored to (the `id` of
@@ -140,7 +148,7 @@
           parentNode;
       }
       return target;
-    },
+    }
 
     /**
      * Hides/closes the hovercard. This occurs when the user triggers the
@@ -184,7 +192,7 @@
       if (this.container.contains(this)) {
         this.container.removeChild(this);
       }
-    },
+    }
 
     /**
      * Shows/opens the hovercard. This occurs when the user triggers the
@@ -207,7 +215,7 @@
 
       // Trigger the transition
       this.classList.add(HOVER_CLASS);
-    },
+    }
 
     /**
      * Updates the hovercard's position based on the `position` attribute
@@ -306,7 +314,7 @@
       // Set the hovercard's position
       cssText += `left:${hovercardLeft}px; top:${hovercardTop}px;`;
       this.style.cssText = cssText;
-    },
+    }
 
     /**
      * Responds to a change in the `for` value and gets the updated `target`
@@ -316,6 +324,8 @@
      */
     _forChanged() {
       this._target = this.target;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrHovercard.is, GrHovercard);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface.js b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface.js
index 2bc8898..1802a4a 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface.js
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface.js
@@ -37,26 +37,34 @@
     REPLY_DIALOG: 'replydialog',
   };
 
-  Polymer({
-    is: 'gr-js-api-interface',
+  /**
+    * @appliesMixin Gerrit.PatchSetMixin
+    */
+  class GrJsApiInterface extends Polymer.mixinBehaviors( [
+    Gerrit.PatchSetBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-js-api-interface'; }
 
-    properties: {
-      _elements: {
-        type: Object,
-        value: {}, // Shared across all instances.
-      },
-      _eventCallbacks: {
-        type: Object,
-        value: {}, // Shared across all instances.
-      },
-    },
+    constructor() {
+      super();
+      this.Element = Element;
+      this.EventType = EventType;
+    }
 
-    behaviors: [
-      Gerrit.PatchSetBehavior,
-    ],
-
-    Element,
-    EventType,
+    static get properties() {
+      return {
+        _elements: {
+          type: Object,
+          value: {}, // Shared across all instances.
+        },
+        _eventCallbacks: {
+          type: Object,
+          value: {}, // Shared across all instances.
+        },
+      };
+    }
 
     handleEvent(type, detail) {
       Gerrit.awaitPluginsLoaded().then(() => {
@@ -82,22 +90,22 @@
             break;
         }
       });
-    },
+    }
 
     addElement(key, el) {
       this._elements[key] = el;
-    },
+    }
 
     getElement(key) {
       return this._elements[key];
-    },
+    }
 
     addEventCallback(eventName, callback) {
       if (!this._eventCallbacks[eventName]) {
         this._eventCallbacks[eventName] = [];
       }
       this._eventCallbacks[eventName].push(callback);
-    },
+    }
 
     canSubmitChange(change, revision) {
       const submitCallbacks = this._getEventCallbacks(EventType.SUBMIT_CHANGE);
@@ -111,14 +119,14 @@
       });
 
       return !cancelSubmit;
-    },
+    }
 
     _removeEventCallbacks() {
       for (const k in EventType) {
         if (!EventType.hasOwnProperty(k)) { continue; }
         this._eventCallbacks[EventType[k]] = [];
       }
-    },
+    }
 
     _handleHistory(detail) {
       for (const cb of this._getEventCallbacks(EventType.HISTORY)) {
@@ -128,7 +136,7 @@
           console.error(err);
         }
       }
-    },
+    }
 
     _handleShowChange(detail) {
       // Note (issue 8221) Shallow clone the change object and add a mergeable
@@ -163,7 +171,7 @@
           console.error(err);
         }
       }
-    },
+    }
 
     handleCommitMessage(change, msg) {
       for (const cb of this._getEventCallbacks(EventType.COMMIT_MSG_EDIT)) {
@@ -173,7 +181,7 @@
           console.error(err);
         }
       }
-    },
+    }
 
     _handleComment(detail) {
       for (const cb of this._getEventCallbacks(EventType.COMMENT)) {
@@ -183,7 +191,7 @@
           console.error(err);
         }
       }
-    },
+    }
 
     _handleLabelChange(detail) {
       for (const cb of this._getEventCallbacks(EventType.LABEL_CHANGE)) {
@@ -193,7 +201,7 @@
           console.error(err);
         }
       }
-    },
+    }
 
     _handleHighlightjsLoaded(detail) {
       for (const cb of this._getEventCallbacks(EventType.HIGHLIGHTJS_LOADED)) {
@@ -203,7 +211,7 @@
           console.error(err);
         }
       }
-    },
+    }
 
     modifyRevertMsg(change, revertMsg, origMsg) {
       for (const cb of this._getEventCallbacks(EventType.REVERT)) {
@@ -214,7 +222,7 @@
         }
       }
       return revertMsg;
-    },
+    }
 
     modifyRevertSubmissionMsg(change, revertSubmissionMsg, origMsg) {
       for (const cb of this._getEventCallbacks(EventType.REVERT_SUBMISSION)) {
@@ -225,7 +233,7 @@
         }
       }
       return revertSubmissionMsg;
-    },
+    }
 
     getDiffLayers(path, changeNum, patchNum) {
       const layers = [];
@@ -239,7 +247,7 @@
         }
       }
       return layers;
-    },
+    }
 
     /**
      * Retrieves coverage data possibly provided by a plugin.
@@ -267,7 +275,7 @@
         }
         return [];
       });
-    },
+    }
 
     getAdminMenuLinks() {
       const links = [];
@@ -276,7 +284,7 @@
         links.push(...adminApi.getMenuLinks());
       }
       return links;
-    },
+    }
 
     getLabelValuesPostRevert(change) {
       let labels = {};
@@ -288,10 +296,12 @@
         }
       }
       return labels;
-    },
+    }
 
     _getEventCallbacks(type) {
       return this._eventCallbacks[type] || [];
-    },
-  });
+    }
+  }
+
+  customElements.define(GrJsApiInterface.is, GrJsApiInterface);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.js b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.js
index 3c27c94..0e529b1 100644
--- a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.js
+++ b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.js
@@ -17,17 +17,21 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-label-info',
+  class GrLabelInfo extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-label-info'; }
 
-    properties: {
-      labelInfo: Object,
-      label: String,
-      /** @type {?} */
-      change: Object,
-      account: Object,
-      mutable: Boolean,
-    },
+    static get properties() {
+      return {
+        labelInfo: Object,
+        label: String,
+        /** @type {?} */
+        change: Object,
+        account: Object,
+        mutable: Boolean,
+      };
+    }
 
     /**
      * @param {!Object} labelInfo
@@ -85,7 +89,7 @@
         }
       }
       return result;
-    },
+    }
 
     /**
      * A user is able to delete a vote iff the mutable property is true and the
@@ -106,7 +110,7 @@
         return '';
       }
       return 'hidden';
-    },
+    }
 
     /**
      * Closure annotation for Polymer.prototype.splice is off.
@@ -133,14 +137,14 @@
                 target.disabled = false;
                 return;
               });
-    },
+    }
 
     _computeValueTooltip(labelInfo, score) {
       if (!labelInfo || !labelInfo.values || !labelInfo.values[score]) {
         return '';
       }
       return labelInfo.values[score];
-    },
+    }
 
     /**
      * @param {!Object} labelInfo
@@ -156,6 +160,8 @@
         }
       }
       return '';
-    },
-  });
+    }
+  }
+
+  customElements.define(GrLabelInfo.is, GrLabelInfo);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-label/gr-label.js b/polygerrit-ui/app/elements/shared/gr-label/gr-label.js
index 0de0881..7d82c9c9 100644
--- a/polygerrit-ui/app/elements/shared/gr-label/gr-label.js
+++ b/polygerrit-ui/app/elements/shared/gr-label/gr-label.js
@@ -17,11 +17,16 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-label',
+  /**
+    * @appliesMixin Gerrit.TooltipMixin
+    */
+  class GrLabel extends Polymer.mixinBehaviors( [
+    Gerrit.TooltipBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-label'; }
+  }
 
-    behaviors: [
-      Gerrit.TooltipBehavior,
-    ],
-  });
+  customElements.define(GrLabel.is, GrLabel);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-labeled-autocomplete/gr-labeled-autocomplete.js b/polygerrit-ui/app/elements/shared/gr-labeled-autocomplete/gr-labeled-autocomplete.js
index fd0f228..d2646af 100644
--- a/polygerrit-ui/app/elements/shared/gr-labeled-autocomplete/gr-labeled-autocomplete.js
+++ b/polygerrit-ui/app/elements/shared/gr-labeled-autocomplete/gr-labeled-autocomplete.js
@@ -17,60 +17,65 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-labeled-autocomplete',
-
+  class GrLabeledAutocomplete extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-labeled-autocomplete'; }
     /**
      * Fired when a value is chosen.
      *
      * @event commit
      */
 
-    properties: {
+    static get properties() {
+      return {
 
-      /**
+        /**
        * Used just like the query property of gr-autocomplete.
        *
        * @type {function(string): Promise<?>}
        */
-      query: {
-        type: Function,
-        value() {
-          return function() {
-            return Promise.resolve([]);
-          };
+        query: {
+          type: Function,
+          value() {
+            return function() {
+              return Promise.resolve([]);
+            };
+          },
         },
-      },
 
-      text: {
-        type: String,
-        value: '',
-        notify: true,
-      },
-      label: String,
-      placeholder: String,
-      disabled: Boolean,
+        text: {
+          type: String,
+          value: '',
+          notify: true,
+        },
+        label: String,
+        placeholder: String,
+        disabled: Boolean,
 
-      _autocompleteThreshold: {
-        type: Number,
-        value: 0,
-        readOnly: true,
-      },
-    },
+        _autocompleteThreshold: {
+          type: Number,
+          value: 0,
+          readOnly: true,
+        },
+      };
+    }
 
     _handleTriggerClick(e) {
       // Stop propagation here so we don't confuse gr-autocomplete, which
       // listens for taps on body to try to determine when it's blurred.
       e.stopPropagation();
       this.$.autocomplete.focus();
-    },
+    }
 
     setText(text) {
       this.$.autocomplete.setText(text);
-    },
+    }
 
     clear() {
       this.setText('');
-    },
-  });
+    }
+  }
+
+  customElements.define(GrLabeledAutocomplete.is, GrLabeledAutocomplete);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-lib-loader/gr-lib-loader.js b/polygerrit-ui/app/elements/shared/gr-lib-loader/gr-lib-loader.js
index 260c819..1fd122c 100644
--- a/polygerrit-ui/app/elements/shared/gr-lib-loader/gr-lib-loader.js
+++ b/polygerrit-ui/app/elements/shared/gr-lib-loader/gr-lib-loader.js
@@ -20,21 +20,25 @@
   const HLJS_PATH = 'bower_components/highlightjs/highlight.min.js';
   const DARK_THEME_PATH = 'styles/themes/dark-theme.html';
 
-  Polymer({
-    is: 'gr-lib-loader',
+  class GrLibLoader extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-lib-loader'; }
 
-    properties: {
-      _hljsState: {
-        type: Object,
+    static get properties() {
+      return {
+        _hljsState: {
+          type: Object,
 
-        // NOTE: intended singleton.
-        value: {
-          configured: false,
-          loading: false,
-          callbacks: [],
+          // NOTE: intended singleton.
+          value: {
+            configured: false,
+            loading: false,
+            callbacks: [],
+          },
         },
-      },
-    },
+      };
+    }
 
     /**
      * Get the HLJS library. Returns a promise that resolves with a reference to
@@ -59,7 +63,7 @@
 
         this._hljsState.callbacks.push(resolve);
       });
-    },
+    }
 
     /**
      * Loads the dark theme document. Returns a promise that resolves with a
@@ -79,7 +83,7 @@
               resolve(cs);
             });
       });
-    },
+    }
 
     /**
      * Execute callbacks awaiting the HLJS lib load.
@@ -94,7 +98,7 @@
         cb(lib);
       }
       this._hljsState.callbacks = [];
-    },
+    }
 
     /**
      * Get the HLJS library, assuming it has been loaded. Configure the library
@@ -109,7 +113,7 @@
         lib.configure({classPrefix: 'gr-diff gr-syntax gr-syntax-'});
       }
       return lib;
-    },
+    }
 
     /**
      * Get the resource path used to load the application. If the application
@@ -121,7 +125,7 @@
         return window.STATIC_RESOURCE_PATH + '/';
       }
       return '/';
-    },
+    }
 
     /**
      * Load and execute a JS file from the lib root.
@@ -143,12 +147,14 @@
         script.onerror = reject;
         Polymer.dom(document.head).appendChild(script);
       });
-    },
+    }
 
     _getHLJSUrl() {
       const root = this._getLibRoot();
       if (!root) { return null; }
       return root + HLJS_PATH;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrLibLoader.is, GrLibLoader);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js b/polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js
index 048e4f5..9239866 100644
--- a/polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js
+++ b/polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js
@@ -17,57 +17,63 @@
 (function() {
   'use strict';
 
+  /**
+    * @appliesMixin Gerrit.TooltipMixin
+    */
   /*
    * The gr-limited-text element is for displaying text with a maximum length
    * (in number of characters) to display. If the length of the text exceeds the
    * configured limit, then an ellipsis indicates that the text was truncated
    * and a tooltip containing the full text is enabled.
    */
+  class GrLimitedText extends Polymer.mixinBehaviors( [
+    Gerrit.TooltipBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-limited-text'; }
 
-  Polymer({
-    is: 'gr-limited-text',
-
-    properties: {
+    static get properties() {
+      return {
       /** The un-truncated text to display. */
-      text: String,
+        text: String,
 
-      /** The maximum length for the text to display before truncating. */
-      limit: {
-        type: Number,
-        value: null,
-      },
+        /** The maximum length for the text to display before truncating. */
+        limit: {
+          type: Number,
+          value: null,
+        },
 
-      /** Boolean property used by Gerrit.TooltipBehavior. */
-      hasTooltip: {
-        type: Boolean,
-        value: false,
-      },
+        /** Boolean property used by Gerrit.TooltipBehavior. */
+        hasTooltip: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * Disable the tooltip.
        * When set to true, will not show tooltip even text is over limit
        */
-      disableTooltip: {
-        type: Boolean,
-        value: false,
-      },
+        disableTooltip: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**
+        /**
        * The maximum number of characters to display in the tooltop.
        */
-      tooltipLimit: {
-        type: Number,
-        value: 1024,
-      },
-    },
+        tooltipLimit: {
+          type: Number,
+          value: 1024,
+        },
+      };
+    }
 
-    observers: [
-      '_updateTitle(text, limit, tooltipLimit)',
-    ],
-
-    behaviors: [
-      Gerrit.TooltipBehavior,
-    ],
+    static get observers() {
+      return [
+        '_updateTitle(text, limit, tooltipLimit)',
+      ];
+    }
 
     /**
      * The text or limit have changed. Recompute whether a tooltip needs to be
@@ -85,13 +91,15 @@
       } else {
         this.removeAttribute('title');
       }
-    },
+    }
 
     _computeDisplayText(text, limit) {
       if (!!limit && !!text && text.length > limit) {
         return text.substr(0, limit - 1) + '…';
       }
       return text;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrLimitedText.is, GrLimitedText);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.js b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.js
index 33a9c25..aaae3d1 100644
--- a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.js
+++ b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.js
@@ -17,41 +17,48 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-linked-chip',
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    */
+  class GrLinkedChip extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-linked-chip'; }
 
-    properties: {
-      href: String,
-      disabled: {
-        type: Boolean,
-        value: false,
-        reflectToAttribute: true,
-      },
-      removable: {
-        type: Boolean,
-        value: false,
-      },
-      text: String,
-      transparentBackground: {
-        type: Boolean,
-        value: false,
-      },
+    static get properties() {
+      return {
+        href: String,
+        disabled: {
+          type: Boolean,
+          value: false,
+          reflectToAttribute: true,
+        },
+        removable: {
+          type: Boolean,
+          value: false,
+        },
+        text: String,
+        transparentBackground: {
+          type: Boolean,
+          value: false,
+        },
 
-      /**  If provided, sets the maximum length of the content. */
-      limit: Number,
-    },
-
-    behaviors: [
-      Gerrit.FireBehavior,
-    ],
+        /**  If provided, sets the maximum length of the content. */
+        limit: Number,
+      };
+    }
 
     _getBackgroundClass(transparent) {
       return transparent ? 'transparentBackground' : '';
-    },
+    }
 
     _handleRemoveTap(e) {
       e.preventDefault();
       this.fire('remove');
-    },
-  });
+    }
+  }
+
+  customElements.define(GrLinkedChip.is, GrLinkedChip);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-linked-text/gr-linked-text.js b/polygerrit-ui/app/elements/shared/gr-linked-text/gr-linked-text.js
index e7247b9..d080999 100644
--- a/polygerrit-ui/app/elements/shared/gr-linked-text/gr-linked-text.js
+++ b/polygerrit-ui/app/elements/shared/gr-linked-text/gr-linked-text.js
@@ -14,13 +14,15 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-(function() {
+(function () {
   'use strict';
+    class GrLinkedText extends Polymer.GestureEventListeners(
+Polymer.LegacyElementMixin(
+Polymer.Element)) {
+        static get is() { return "gr-linked-text"; } 
 
-  Polymer({
-    is: 'gr-linked-text',
 
-    properties: {
+        static get properties() { return {
       removeZeroWidthSpace: Boolean,
       content: {
         type: String,
@@ -37,11 +39,10 @@
         reflectToAttribute: true,
       },
       config: Object,
-    },
-
-    observers: [
+    }; }
+        static get observers() { return [
       '_contentOrConfigChanged(content, config)',
-    ],
+    ]; }
 
     _contentChanged(content) {
       // In the case where the config may not be set (perhaps due to the
@@ -49,7 +50,7 @@
       // prevent waiting on the config to display the text.
       if (this.config != null) { return; }
       this.$.output.textContent = content;
-    },
+    }
 
     /**
      * Because either the source text or the linkification config has changed,
@@ -74,7 +75,7 @@
         anchor.setAttribute('target', '_blank');
         anchor.setAttribute('rel', 'noopener');
       });
-    },
+    }
 
     /**
      * This method is called when the GrLikTextParser emits a partial result
@@ -100,6 +101,7 @@
       } else if (fragment) {
         output.appendChild(fragment);
       }
-    },
-  });
+    }
+    }
+    customElements.define(GrLinkedText.is, GrLinkedText);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js b/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js
index 8d81030..9d5d8f5 100644
--- a/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js
+++ b/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js
@@ -19,31 +19,39 @@
 
   const REQUEST_DEBOUNCE_INTERVAL_MS = 200;
 
-  Polymer({
-    is: 'gr-list-view',
+  /**
+    * @appliesMixin Gerrit.BaseUrlMixin
+    * @appliesMixin Gerrit.FireMixin
+    * @appliesMixin Gerrit.URLEncodingMixin
+    */
+  class GrListView extends Polymer.mixinBehaviors( [
+    Gerrit.BaseUrlBehavior,
+    Gerrit.FireBehavior,
+    Gerrit.URLEncodingBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-list-view'; }
 
-    properties: {
-      createNew: Boolean,
-      items: Array,
-      itemsPerPage: Number,
-      filter: {
-        type: String,
-        observer: '_filterChanged',
-      },
-      offset: Number,
-      loading: Boolean,
-      path: String,
-    },
-
-    behaviors: [
-      Gerrit.BaseUrlBehavior,
-      Gerrit.FireBehavior,
-      Gerrit.URLEncodingBehavior,
-    ],
+    static get properties() {
+      return {
+        createNew: Boolean,
+        items: Array,
+        itemsPerPage: Number,
+        filter: {
+          type: String,
+          observer: '_filterChanged',
+        },
+        offset: Number,
+        loading: Boolean,
+        path: String,
+      };
+    }
 
     detached() {
+      super.detached();
       this.cancelDebouncer('reload');
-    },
+    }
 
     _filterChanged(newFilter, oldFilter) {
       if (!newFilter && !oldFilter) {
@@ -51,7 +59,7 @@
       }
 
       this._debounceReload(newFilter);
-    },
+    }
 
     _debounceReload(filter) {
       this.debounce('reload', () => {
@@ -61,11 +69,11 @@
         }
         page.show(this.path);
       }, REQUEST_DEBOUNCE_INTERVAL_MS);
-    },
+    }
 
     _createNewItem() {
       this.fire('create-clicked');
-    },
+    }
 
     _computeNavLink(offset, direction, itemsPerPage, filter, path) {
       // Offset could be a string when passed from the router.
@@ -79,15 +87,15 @@
         href += ',' + newOffset;
       }
       return href;
-    },
+    }
 
     _computeCreateClass(createNew) {
       return createNew ? 'show' : '';
-    },
+    }
 
     _hidePrevArrow(loading, offset) {
       return loading || offset === 0;
-    },
+    }
 
     _hideNextArrow(loading, items) {
       if (loading || !items || !items.length) {
@@ -95,6 +103,8 @@
       }
       const lastPage = items.length < this.itemsPerPage + 1;
       return lastPage;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrListView.is, GrListView);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.js b/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.js
index 8623458..9c7e680 100644
--- a/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.js
+++ b/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.js
@@ -21,9 +21,16 @@
   const AWAIT_STEP = 5;
   const BREAKPOINT_FULLSCREEN_OVERLAY = '50em';
 
-  Polymer({
-    is: 'gr-overlay',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    */
+  class GrOverlay extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+    Polymer.IronOverlayBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-overlay'; }
     /**
      * Fired when a fullscreen overlay is closed
      *
@@ -36,22 +43,22 @@
      * @event fullscreen-overlay-opened
      */
 
-    properties: {
-      _fullScreenOpen: {
-        type: Boolean,
-        value: false,
-      },
-    },
+    static get properties() {
+      return {
+        _fullScreenOpen: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
 
-    behaviors: [
-      Gerrit.FireBehavior,
-      Polymer.IronOverlayBehavior,
-    ],
-
-    listeners: {
-      'iron-overlay-closed': '_close',
-      'iron-overlay-cancelled': '_close',
-    },
+    created() {
+      super.created();
+      this.addEventListener('iron-overlay-closed',
+          () => this._close());
+      this.addEventListener('iron-overlay-cancelled',
+          () => this._close());
+    }
 
     open(...args) {
       return new Promise(resolve => {
@@ -62,18 +69,18 @@
         }
         this._awaitOpen(resolve);
       });
-    },
+    }
 
     _isMobile() {
       return window.matchMedia(`(max-width: ${BREAKPOINT_FULLSCREEN_OVERLAY})`);
-    },
+    }
 
     _close() {
       if (this._fullScreenOpen) {
         this.fire('fullscreen-overlay-closed');
         this._fullScreenOpen = false;
       }
-    },
+    }
 
     /**
      * Override the focus stops that iron-overlay-behavior tries to find.
@@ -81,7 +88,7 @@
     setFocusStops(stops) {
       this.__firstFocusableNode = stops.start;
       this.__lastFocusableNode = stops.end;
-    },
+    }
 
     /**
      * NOTE: (wyatta) Slightly hacky way to listen to the overlay actually
@@ -99,10 +106,12 @@
         }, AWAIT_STEP);
       };
       step.call(this);
-    },
+    }
 
     _id() {
       return this.getAttribute('id') || 'global';
-    },
-  });
+    }
+  }
+
+  customElements.define(GrOverlay.is, GrOverlay);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-page-nav/gr-page-nav.js b/polygerrit-ui/app/elements/shared/gr-page-nav/gr-page-nav.js
index 2e05607..23389ee 100644
--- a/polygerrit-ui/app/elements/shared/gr-page-nav/gr-page-nav.js
+++ b/polygerrit-ui/app/elements/shared/gr-page-nav/gr-page-nav.js
@@ -17,20 +17,26 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-page-nav',
+  class GrPageNav extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-page-nav'; }
 
-    properties: {
-      _headerHeight: Number,
-    },
+    static get properties() {
+      return {
+        _headerHeight: Number,
+      };
+    }
 
     attached() {
+      super.attached();
       this.listen(window, 'scroll', '_handleBodyScroll');
-    },
+    }
 
     detached() {
+      super.detached();
       this.unlisten(window, 'scroll', '_handleBodyScroll');
-    },
+    }
 
     _handleBodyScroll() {
       if (this._headerHeight === undefined) {
@@ -45,20 +51,22 @@
 
       this.$.nav.classList.toggle('pinned',
           this._getScrollY() >= this._headerHeight);
-    },
+    }
 
     /* Functions used for test purposes */
     _getOffsetParent(element) {
       if (!element || !element.offsetParent) { return ''; }
       return element.offsetParent;
-    },
+    }
 
     _getOffsetTop(element) {
       return element.offsetTop;
-    },
+    }
 
     _getScrollY() {
       return window.scrollY;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrPageNav.is, GrPageNav);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker.js b/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker.js
index e2298c3..47979f1 100644
--- a/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker.js
+++ b/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker.js
@@ -20,47 +20,54 @@
   const SUGGESTIONS_LIMIT = 15;
   const REF_PREFIX = 'refs/heads/';
 
-  Polymer({
-    is: 'gr-repo-branch-picker',
+  /**
+    * @appliesMixin Gerrit.URLEncodingMixin
+    */
+  class GrRepoBranchPicker extends Polymer.mixinBehaviors( [
+    Gerrit.URLEncodingBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-repo-branch-picker'; }
 
-    properties: {
-      repo: {
-        type: String,
-        notify: true,
-        observer: '_repoChanged',
-      },
-      branch: {
-        type: String,
-        notify: true,
-      },
-      _branchDisabled: Boolean,
-      _query: {
-        type: Function,
-        value() {
-          return this._getRepoBranchesSuggestions.bind(this);
+    static get properties() {
+      return {
+        repo: {
+          type: String,
+          notify: true,
+          observer: '_repoChanged',
         },
-      },
-      _repoQuery: {
-        type: Function,
-        value() {
-          return this._getRepoSuggestions.bind(this);
+        branch: {
+          type: String,
+          notify: true,
         },
-      },
-    },
-
-    behaviors: [
-      Gerrit.URLEncodingBehavior,
-    ],
+        _branchDisabled: Boolean,
+        _query: {
+          type: Function,
+          value() {
+            return this._getRepoBranchesSuggestions.bind(this);
+          },
+        },
+        _repoQuery: {
+          type: Function,
+          value() {
+            return this._getRepoSuggestions.bind(this);
+          },
+        },
+      };
+    }
 
     attached() {
+      super.attached();
       if (this.repo) {
         this.$.repoInput.setText(this.repo);
       }
-    },
+    }
 
     ready() {
+      super.ready();
       this._branchDisabled = !this.repo;
-    },
+    }
 
     _getRepoBranchesSuggestions(input) {
       if (!this.repo) { return Promise.resolve([]); }
@@ -69,19 +76,19 @@
       }
       return this.$.restAPI.getRepoBranches(input, this.repo, SUGGESTIONS_LIMIT)
           .then(this._branchResponseToSuggestions.bind(this));
-    },
+    }
 
     _getRepoSuggestions(input) {
       return this.$.restAPI.getRepos(input, SUGGESTIONS_LIMIT)
           .then(this._repoResponseToSuggestions.bind(this));
-    },
+    }
 
     _repoResponseToSuggestions(res) {
       return res.map(repo => ({
         name: repo.name,
         value: this.singleDecodeURL(repo.id),
       }));
-    },
+    }
 
     _branchResponseToSuggestions(res) {
       return Object.keys(res).map(key => {
@@ -91,19 +98,21 @@
         }
         return {name: branch, value: branch};
       });
-    },
+    }
 
     _repoCommitted(e) {
       this.repo = e.detail.value;
-    },
+    }
 
     _branchCommitted(e) {
       this.branch = e.detail.value;
-    },
+    }
 
     _repoChanged() {
       this.$.branchInput.clear();
       this._branchDisabled = !this.repo;
-    },
-  });
+    }
+  }
+
+  customElements.define(GrRepoBranchPicker.is, GrRepoBranchPicker);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
index 043a5ed..a1a7f90 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
@@ -39,16 +39,21 @@
   const ANONYMIZED_REVISION_BASE_URL = ANONYMIZED_CHANGE_BASE_URL +
       '/revisions/*';
 
-  Polymer({
-    is: 'gr-rest-api-interface',
-
-    behaviors: [
-      Gerrit.FireBehavior,
-      Gerrit.PathListBehavior,
-      Gerrit.PatchSetBehavior,
-      Gerrit.RESTClientBehavior,
-    ],
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    * @appliesMixin Gerrit.PathListMixin
+    * @appliesMixin Gerrit.PatchSetMixin
+    * @appliesMixin Gerrit.RESTClientMixin
+    */
+  class GrRestApiInterface extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+    Gerrit.PathListBehavior,
+    Gerrit.PatchSetBehavior,
+    Gerrit.RESTClientBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-rest-api-interface'; }
     /**
      * Fired when an server error occurs.
      *
@@ -73,43 +78,49 @@
      * @event rpc-log
      */
 
-    properties: {
-      _cache: {
-        type: Object,
-        value: new SiteBasedCache(), // Shared across instances.
-      },
-      _credentialCheck: {
-        type: Object,
-        value: {checking: false}, // Shared across instances.
-      },
-      _sharedFetchPromises: {
-        type: Object,
-        value: new FetchPromisesCache(), // Shared across instances.
-      },
-      _pendingRequests: {
-        type: Object,
-        value: {}, // Intentional to share the object across instances.
-      },
-      _etags: {
-        type: Object,
-        value: new GrEtagDecorator(), // Share across instances.
-      },
-      /**
+    constructor() {
+      super();
+      this.JSON_PREFIX = JSON_PREFIX;
+    }
+
+    static get properties() {
+      return {
+        _cache: {
+          type: Object,
+          value: new SiteBasedCache(), // Shared across instances.
+        },
+        _credentialCheck: {
+          type: Object,
+          value: {checking: false}, // Shared across instances.
+        },
+        _sharedFetchPromises: {
+          type: Object,
+          value: new FetchPromisesCache(), // Shared across instances.
+        },
+        _pendingRequests: {
+          type: Object,
+          value: {}, // Intentional to share the object across instances.
+        },
+        _etags: {
+          type: Object,
+          value: new GrEtagDecorator(), // Share across instances.
+        },
+        /**
        * Used to maintain a mapping of changeNums to project names.
        */
-      _projectLookup: {
-        type: Object,
-        value: {}, // Intentional to share the object across instances.
-      },
-      _auth: {
-        type: Object,
-        value: Gerrit.Auth, // Share across instances.
-      },
-    },
-
-    JSON_PREFIX,
+        _projectLookup: {
+          type: Object,
+          value: {}, // Intentional to share the object across instances.
+        },
+        _auth: {
+          type: Object,
+          value: Gerrit.Auth, // Share across instances.
+        },
+      };
+    }
 
     created() {
+      super.created();
       /* Polymer 1 and Polymer 2 have slightly different lifecycle.
       * Differences are not very well documented (see
       * https://github.com/Polymer/old-docs-site/issues/2322).
@@ -130,12 +141,13 @@
       //
 
       this._initRestApiHelper();
-    },
+    }
 
     ready() {
+      super.ready();
       // See comments in created()
       this._initRestApiHelper();
-    },
+    }
 
     _initRestApiHelper() {
       if (this._restApiHelper) {
@@ -146,12 +158,12 @@
         this._restApiHelper = new GrRestApiHelper(this._cache, this._auth,
             this._sharedFetchPromises, this._credentialCheck, this);
       }
-    },
+    }
 
     _fetchSharedCacheURL(req) {
       // Cache is shared across instances
       return this._restApiHelper.fetchCacheURL(req);
-    },
+    }
 
     /**
      * @param {!Object} response
@@ -159,7 +171,7 @@
      */
     getResponseObject(response) {
       return this._restApiHelper.getResponseObject(response);
-    },
+    }
 
     getConfig(noCache) {
       if (!noCache) {
@@ -173,7 +185,7 @@
         url: '/config/server/info',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     getRepo(repo, opt_errFn) {
       // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
@@ -183,7 +195,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*',
       });
-    },
+    }
 
     getProjectConfig(repo, opt_errFn) {
       // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
@@ -193,7 +205,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/config',
       });
-    },
+    }
 
     getRepoAccess(repo) {
       // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
@@ -202,7 +214,7 @@
         url: '/access/?project=' + encodeURIComponent(repo),
         anonymizedUrl: '/access/?project=*',
       });
-    },
+    }
 
     getRepoDashboards(repo, opt_errFn) {
       // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
@@ -212,7 +224,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/dashboards?inherited',
       });
-    },
+    }
 
     saveRepoConfig(repo, config, opt_errFn) {
       // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
@@ -226,7 +238,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/config',
       });
-    },
+    }
 
     runRepoGC(repo, opt_errFn) {
       if (!repo) { return ''; }
@@ -240,7 +252,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/gc',
       });
-    },
+    }
 
     /**
      * @param {?Object} config
@@ -258,7 +270,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*',
       });
-    },
+    }
 
     /**
      * @param {?Object} config
@@ -274,7 +286,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/groups/*',
       });
-    },
+    }
 
     getGroupConfig(group, opt_errFn) {
       return this._restApiHelper.fetchJSON({
@@ -282,7 +294,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/groups/*/detail',
       });
-    },
+    }
 
     /**
      * @param {string} repo
@@ -302,7 +314,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/branches/*',
       });
-    },
+    }
 
     /**
      * @param {string} repo
@@ -322,7 +334,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/tags/*',
       });
-    },
+    }
 
     /**
      * @param {string} name
@@ -343,7 +355,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/branches/*',
       });
-    },
+    }
 
     /**
      * @param {string} name
@@ -364,7 +376,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/tags/*',
       });
-    },
+    }
 
     /**
      * @param {!string} groupName
@@ -378,7 +390,7 @@
       };
       return this._fetchSharedCacheURL(req)
           .then(configs => configs.hasOwnProperty(groupName));
-    },
+    }
 
     getGroupMembers(groupName, opt_errFn) {
       const encodeName = encodeURIComponent(groupName);
@@ -387,14 +399,14 @@
         errFn: opt_errFn,
         anonymizedUrl: '/groups/*/members',
       });
-    },
+    }
 
     getIncludedGroup(groupName) {
       return this._restApiHelper.fetchJSON({
         url: `/groups/${encodeURIComponent(groupName)}/groups/`,
         anonymizedUrl: '/groups/*/groups',
       });
-    },
+    }
 
     saveGroupName(groupId, name) {
       const encodeId = encodeURIComponent(groupId);
@@ -404,7 +416,7 @@
         body: {name},
         anonymizedUrl: '/groups/*/name',
       });
-    },
+    }
 
     saveGroupOwner(groupId, ownerId) {
       const encodeId = encodeURIComponent(groupId);
@@ -414,7 +426,7 @@
         body: {owner: ownerId},
         anonymizedUrl: '/groups/*/owner',
       });
-    },
+    }
 
     saveGroupDescription(groupId, description) {
       const encodeId = encodeURIComponent(groupId);
@@ -424,7 +436,7 @@
         body: {description},
         anonymizedUrl: '/groups/*/description',
       });
-    },
+    }
 
     saveGroupOptions(groupId, options) {
       const encodeId = encodeURIComponent(groupId);
@@ -434,7 +446,7 @@
         body: options,
         anonymizedUrl: '/groups/*/options',
       });
-    },
+    }
 
     getGroupAuditLog(group, opt_errFn) {
       return this._fetchSharedCacheURL({
@@ -442,7 +454,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/groups/*/log.audit',
       });
-    },
+    }
 
     saveGroupMembers(groupName, groupMembers) {
       const encodeName = encodeURIComponent(groupName);
@@ -453,7 +465,7 @@
         parseResponse: true,
         anonymizedUrl: '/groups/*/members/*',
       });
-    },
+    }
 
     saveIncludedGroup(groupName, includedGroup, opt_errFn) {
       const encodeName = encodeURIComponent(groupName);
@@ -469,7 +481,7 @@
           return this.getResponseObject(response);
         }
       });
-    },
+    }
 
     deleteGroupMembers(groupName, groupMembers) {
       const encodeName = encodeURIComponent(groupName);
@@ -479,7 +491,7 @@
         url: `/groups/${encodeName}/members/${encodeMember}`,
         anonymizedUrl: '/groups/*/members/*',
       });
-    },
+    }
 
     deleteIncludedGroup(groupName, includedGroup) {
       const encodeName = encodeURIComponent(groupName);
@@ -489,14 +501,14 @@
         url: `/groups/${encodeName}/groups/${encodeIncludedGroup}`,
         anonymizedUrl: '/groups/*/groups/*',
       });
-    },
+    }
 
     getVersion() {
       return this._fetchSharedCacheURL({
         url: '/config/server/version',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     getDiffPreferences() {
       return this.getLoggedIn().then(loggedIn => {
@@ -527,7 +539,7 @@
           theme: 'DEFAULT',
         });
       });
-    },
+    }
 
     getEditPreferences() {
       return this.getLoggedIn().then(loggedIn => {
@@ -558,7 +570,7 @@
           theme: 'DEFAULT',
         });
       });
-    },
+    }
 
     /**
      * @param {?Object} prefs
@@ -578,7 +590,7 @@
         errFn: opt_errFn,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {?Object} prefs
@@ -594,7 +606,7 @@
         errFn: opt_errFn,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {?Object} prefs
@@ -610,7 +622,7 @@
         errFn: opt_errFn,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     getAccount() {
       return this._fetchSharedCacheURL({
@@ -622,7 +634,7 @@
           }
         },
       });
-    },
+    }
 
     getAvatarChangeUrl() {
       return this._fetchSharedCacheURL({
@@ -634,14 +646,14 @@
           }
         },
       });
-    },
+    }
 
     getExternalIds() {
       return this._restApiHelper.fetchJSON({
         url: '/accounts/self/external.ids',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     deleteAccountIdentity(id) {
       return this._restApiHelper.send({
@@ -651,7 +663,7 @@
         parseResponse: true,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {string} userId the ID of the user usch as an email address.
@@ -662,14 +674,14 @@
         url: `/accounts/${encodeURIComponent(userId)}/detail`,
         anonymizedUrl: '/accounts/*/detail',
       });
-    },
+    }
 
     getAccountEmails() {
       return this._fetchSharedCacheURL({
         url: '/accounts/self/emails',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {string} email
@@ -682,7 +694,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/account/self/emails/*',
       });
-    },
+    }
 
     /**
      * @param {string} email
@@ -695,7 +707,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/accounts/self/email/*',
       });
-    },
+    }
 
     /**
      * @param {string} email
@@ -724,7 +736,7 @@
           this._cache.set('/accounts/self/emails', emails);
         }
       });
-    },
+    }
 
     /**
      * @param {?Object} obj
@@ -738,7 +750,7 @@
         this._cache.set('/accounts/self/detail',
             Object.assign({}, cachedAccount, obj));
       }
-    },
+    }
 
     /**
      * @param {string} name
@@ -755,7 +767,7 @@
       };
       return this._restApiHelper.send(req)
           .then(newName => this._updateCachedAccount({name: newName}));
-    },
+    }
 
     /**
      * @param {string} username
@@ -772,7 +784,7 @@
       };
       return this._restApiHelper.send(req)
           .then(newName => this._updateCachedAccount({username: newName}));
-    },
+    }
 
     /**
      * @param {string} status
@@ -789,28 +801,28 @@
       };
       return this._restApiHelper.send(req)
           .then(newStatus => this._updateCachedAccount({status: newStatus}));
-    },
+    }
 
     getAccountStatus(userId) {
       return this._restApiHelper.fetchJSON({
         url: `/accounts/${encodeURIComponent(userId)}/status`,
         anonymizedUrl: '/accounts/*/status',
       });
-    },
+    }
 
     getAccountGroups() {
       return this._restApiHelper.fetchJSON({
         url: '/accounts/self/groups',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     getAccountAgreements() {
       return this._restApiHelper.fetchJSON({
         url: '/accounts/self/agreements',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     saveAccountAgreement(name) {
       return this._restApiHelper.send({
@@ -819,7 +831,7 @@
         body: name,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {string=} opt_params
@@ -835,7 +847,7 @@
         url: '/accounts/self/capabilities' + queryString,
         anonymizedUrl: '/accounts/self/capabilities?q=*',
       });
-    },
+    }
 
     getLoggedIn() {
       return this.getAccount().then(account => {
@@ -843,7 +855,7 @@
       }).catch(() => {
         return false;
       });
-    },
+    }
 
     getIsAdmin() {
       return this.getLoggedIn().then(isLoggedIn => {
@@ -855,18 +867,18 @@
       }).then(capabilities => {
         return capabilities && capabilities.administrateServer;
       });
-    },
+    }
 
     checkCredentials() {
       return this._restApiHelper.checkCredentials();
-    },
+    }
 
     getDefaultPreferences() {
       return this._fetchSharedCacheURL({
         url: '/config/server/preferences',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     getPreferences() {
       return this.getLoggedIn().then(loggedIn => {
@@ -892,14 +904,14 @@
           size_bar_in_change_table: true,
         });
       });
-    },
+    }
 
     getWatchedProjects() {
       return this._fetchSharedCacheURL({
         url: '/accounts/self/watched.projects',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {string} projects
@@ -914,7 +926,7 @@
         parseResponse: true,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {string} projects
@@ -928,11 +940,11 @@
         errFn: opt_errFn,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     _isNarrowScreen() {
       return window.innerWidth < MAX_UNIFIED_DEFAULT_WINDOW_WIDTH_PX;
-    },
+    }
 
     /**
      * @param {number=} opt_changesPerPage
@@ -988,7 +1000,7 @@
         }
         return response;
       });
-    },
+    }
 
     /**
      * Inserts a change into _projectLookup iff it has a valid structure.
@@ -998,7 +1010,7 @@
       if (change && change.project && change._number) {
         this.setInProjectLookup(change._number, change.project);
       }
-    },
+    }
 
     /**
      * TODO (beckysiegel) this needs to be rewritten with the optional param
@@ -1012,7 +1024,7 @@
     getChangeActionURL(changeNum, opt_patchNum, endpoint) {
       return this._changeBaseURL(changeNum, opt_patchNum)
           .then(url => url + endpoint);
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1043,7 +1055,7 @@
             changeNum, optionsHex, opt_errFn, opt_cancelCondition)
             .then(GrReviewerUpdatesParser.parse);
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1059,7 +1071,7 @@
       );
       return this._getChangeDetail(changeNum, optionsHex, opt_errFn,
           opt_cancelCondition);
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1109,7 +1121,7 @@
           });
         });
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1122,7 +1134,7 @@
         patchNum,
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1143,7 +1155,7 @@
         params,
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1161,7 +1173,7 @@
         endpoint,
         anonymizedEndpoint,
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1176,7 +1188,7 @@
         patchNum,
         anonymizedEndpoint: '/files?q=*',
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1189,7 +1201,7 @@
           res.files);
       }
       return this.getChangeFiles(changeNum, patchRange);
-    },
+    }
 
     /**
      * The closure compiler doesn't realize this.specialFilePathCompare is
@@ -1201,7 +1213,7 @@
         if (!files) return;
         return Object.keys(files).sort(this.specialFilePathCompare);
       });
-    },
+    }
 
     getChangeRevisionActions(changeNum, patchNum) {
       const req = {
@@ -1219,7 +1231,7 @@
         }
         return revisionActions;
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1229,7 +1241,7 @@
     getChangeSuggestedReviewers(changeNum, inputVal, opt_errFn) {
       return this._getChangeSuggestedGroup('REVIEWER', changeNum, inputVal,
           opt_errFn);
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1239,7 +1251,7 @@
     getChangeSuggestedCCs(changeNum, inputVal, opt_errFn) {
       return this._getChangeSuggestedGroup('CC', changeNum, inputVal,
           opt_errFn);
-    },
+    }
 
     _getChangeSuggestedGroup(reviewerState, changeNum, inputVal, opt_errFn) {
       // More suggestions may obscure content underneath in the reply dialog,
@@ -1253,7 +1265,7 @@
         params,
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1264,7 +1276,7 @@
         endpoint: '/in',
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     _computeFilter(filter) {
       if (filter && filter.startsWith('^')) {
@@ -1275,7 +1287,7 @@
         filter = '';
       }
       return filter;
-    },
+    }
 
     /**
      * @param {string} filter
@@ -1287,7 +1299,7 @@
 
       return `/groups/?n=${groupsPerPage + 1}&S=${offset}` +
         this._computeFilter(filter);
-    },
+    }
 
     /**
      * @param {string} filter
@@ -1323,15 +1335,15 @@
 
       return `/projects/?n=${reposPerPage + 1}&S=${offset}` +
         `&query=${encodedFilter}`;
-    },
+    }
 
     invalidateGroupsCache() {
       this._restApiHelper.invalidateFetchPromisesPrefix('/groups/?');
-    },
+    }
 
     invalidateReposCache() {
       this._restApiHelper.invalidateFetchPromisesPrefix('/projects/?');
-    },
+    }
 
     /**
      * @param {string} filter
@@ -1346,7 +1358,7 @@
         url,
         anonymizedUrl: '/groups/?*',
       });
-    },
+    }
 
     /**
      * @param {string} filter
@@ -1363,7 +1375,7 @@
         url,
         anonymizedUrl: '/projects/?*',
       });
-    },
+    }
 
     setRepoHead(repo, ref) {
       // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
@@ -1374,7 +1386,7 @@
         body: {ref},
         anonymizedUrl: '/projects/*/HEAD',
       });
-    },
+    }
 
     /**
      * @param {string} filter
@@ -1397,7 +1409,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/branches?*',
       });
-    },
+    }
 
     /**
      * @param {string} filter
@@ -1421,7 +1433,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/tags',
       });
-    },
+    }
 
     /**
      * @param {string} filter
@@ -1440,7 +1452,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/plugins/?all',
       });
-    },
+    }
 
     getRepoAccessRights(repoName, opt_errFn) {
       // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
@@ -1450,7 +1462,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/access',
       });
-    },
+    }
 
     setRepoAccessRights(repoName, repoInfo) {
       // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
@@ -1461,7 +1473,7 @@
         body: repoInfo,
         anonymizedUrl: '/projects/*/access',
       });
-    },
+    }
 
     setRepoAccessRightsForReview(projectName, projectInfo) {
       return this._restApiHelper.send({
@@ -1471,7 +1483,7 @@
         parseResponse: true,
         anonymizedUrl: '/projects/*/access:review',
       });
-    },
+    }
 
     /**
      * @param {string} inputVal
@@ -1487,7 +1499,7 @@
         params,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {string} inputVal
@@ -1507,7 +1519,7 @@
         params,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {string} inputVal
@@ -1526,15 +1538,15 @@
         params,
         anonymizedUrl: '/accounts/?n=*',
       });
-    },
+    }
 
     addChangeReviewer(changeNum, reviewerID) {
       return this._sendChangeReviewerRequest('POST', changeNum, reviewerID);
-    },
+    }
 
     removeChangeReviewer(changeNum, reviewerID) {
       return this._sendChangeReviewerRequest('DELETE', changeNum, reviewerID);
-    },
+    }
 
     _sendChangeReviewerRequest(method, changeNum, reviewerID) {
       return this.getChangeActionURL(changeNum, null, '/reviewers')
@@ -1553,7 +1565,7 @@
 
             return this._restApiHelper.send({method, url, body});
           });
-    },
+    }
 
     getRelatedChanges(changeNum, patchNum) {
       return this._getChangeURLAndFetch({
@@ -1562,7 +1574,7 @@
         patchNum,
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     getChangesSubmittedTogether(changeNum) {
       return this._getChangeURLAndFetch({
@@ -1570,7 +1582,7 @@
         endpoint: '/submitted_together?o=NON_VISIBLE_CHANGES',
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     getChangeConflicts(changeNum) {
       const options = this.listChangesOptionsToHex(
@@ -1586,7 +1598,7 @@
         params,
         anonymizedUrl: '/changes/conflicts:*',
       });
-    },
+    }
 
     getChangeCherryPicks(project, changeID, changeNum) {
       const options = this.listChangesOptionsToHex(
@@ -1608,7 +1620,7 @@
         params,
         anonymizedUrl: '/changes/change:*',
       });
-    },
+    }
 
     getChangesWithSameTopic(topic, changeNum) {
       const options = this.listChangesOptionsToHex(
@@ -1631,7 +1643,7 @@
         params,
         anonymizedUrl: '/changes/topic:*',
       });
-    },
+    }
 
     getReviewedFiles(changeNum, patchNum) {
       return this._getChangeURLAndFetch({
@@ -1640,7 +1652,7 @@
         patchNum,
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1658,7 +1670,7 @@
         errFn: opt_errFn,
         anonymizedEndpoint: '/files/*/reviewed',
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1679,7 +1691,7 @@
           errFn: opt_errFn,
         });
       });
-    },
+    }
 
     getChangeEdit(changeNum, opt_download_commands) {
       const params = opt_download_commands ? {'download-commands': true} : null;
@@ -1692,7 +1704,7 @@
           reportEndpointAsIs: true,
         });
       });
-    },
+    }
 
     /**
      * @param {string} project
@@ -1722,7 +1734,7 @@
         parseResponse: true,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1750,7 +1762,7 @@
           return {content, type, ok: true};
         });
       });
-    },
+    }
 
     /**
      * Gets a file in a specific change and revision.
@@ -1769,7 +1781,7 @@
         headers: {Accept: 'application/json'},
         anonymizedEndpoint: '/files/*/content',
       });
-    },
+    }
 
     /**
      * Gets a file in a change edit.
@@ -1784,7 +1796,7 @@
         headers: {Accept: 'application/json'},
         anonymizedEndpoint: '/edit/*',
       });
-    },
+    }
 
     rebaseChangeEdit(changeNum) {
       return this._getChangeURLAndSend({
@@ -1793,7 +1805,7 @@
         endpoint: '/edit:rebase',
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     deleteChangeEdit(changeNum) {
       return this._getChangeURLAndSend({
@@ -1802,7 +1814,7 @@
         endpoint: '/edit',
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     restoreFileInChangeEdit(changeNum, restore_path) {
       return this._getChangeURLAndSend({
@@ -1812,7 +1824,7 @@
         body: {restore_path},
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     renameFileInChangeEdit(changeNum, old_path, new_path) {
       return this._getChangeURLAndSend({
@@ -1822,7 +1834,7 @@
         body: {old_path, new_path},
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     deleteFileInChangeEdit(changeNum, path) {
       return this._getChangeURLAndSend({
@@ -1831,7 +1843,7 @@
         endpoint: '/edit/' + encodeURIComponent(path),
         anonymizedEndpoint: '/edit/*',
       });
-    },
+    }
 
     saveChangeEdit(changeNum, path, contents) {
       return this._getChangeURLAndSend({
@@ -1842,7 +1854,7 @@
         contentType: 'text/plain',
         anonymizedEndpoint: '/edit/*',
       });
-    },
+    }
 
     // Deprecated, prefer to use putChangeCommitMessage instead.
     saveChangeCommitMessageEdit(changeNum, message) {
@@ -1853,7 +1865,7 @@
         body: {message},
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     publishChangeEdit(changeNum) {
       return this._getChangeURLAndSend({
@@ -1862,7 +1874,7 @@
         endpoint: '/edit:publish',
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     putChangeCommitMessage(changeNum, message) {
       return this._getChangeURLAndSend({
@@ -1872,7 +1884,7 @@
         body: {message},
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     saveChangeStarred(changeNum, starred) {
       // Some servers may require the project name to be provided
@@ -1887,7 +1899,7 @@
           anonymizedUrl: '/accounts/self/starred.changes/*',
         });
       });
-    },
+    }
 
     saveChangeReviewed(changeNum, reviewed) {
       return this._getChangeURLAndSend({
@@ -1895,7 +1907,7 @@
         method: 'PUT',
         endpoint: reviewed ? '/reviewed' : '/unreviewed',
       });
-    },
+    }
 
     /**
      * Public version of the _restApiHelper.send method preserved for plugins.
@@ -1919,7 +1931,7 @@
         contentType: opt_contentType,
         headers: opt_headers,
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1961,7 +1973,7 @@
       }
 
       return this._getChangeURLAndFetch(req);
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1973,7 +1985,7 @@
     getDiffComments(changeNum, opt_basePatchNum, opt_patchNum, opt_path) {
       return this._getDiffComments(changeNum, '/comments', opt_basePatchNum,
           opt_patchNum, opt_path);
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -1985,7 +1997,7 @@
     getDiffRobotComments(changeNum, opt_basePatchNum, opt_patchNum, opt_path) {
       return this._getDiffComments(changeNum, '/robotcomments',
           opt_basePatchNum, opt_patchNum, opt_path);
-    },
+    }
 
     /**
      * If the user is logged in, fetch the user's draft diff comments. If there
@@ -2004,7 +2016,7 @@
         return this._getDiffComments(changeNum, '/drafts', opt_basePatchNum,
             opt_patchNum, opt_path);
       });
-    },
+    }
 
     _setRange(comments, comment) {
       if (comment.in_reply_to && !comment.range) {
@@ -2016,7 +2028,7 @@
         }
       }
       return comment;
-    },
+    }
 
     _setRanges(comments) {
       comments = comments || [];
@@ -2027,7 +2039,7 @@
         this._setRange(comments, comment);
       }
       return comments;
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -2100,7 +2112,7 @@
           comments,
         });
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -2110,15 +2122,15 @@
     _getDiffCommentsFetchURL(changeNum, endpoint, opt_patchNum) {
       return this._changeBaseURL(changeNum, opt_patchNum)
           .then(url => url + endpoint);
-    },
+    }
 
     saveDiffDraft(changeNum, patchNum, draft) {
       return this._sendDiffDraftRequest('PUT', changeNum, patchNum, draft);
-    },
+    }
 
     deleteDiffDraft(changeNum, patchNum, draft) {
       return this._sendDiffDraftRequest('DELETE', changeNum, patchNum, draft);
-    },
+    }
 
     /**
      * @returns {boolean} Whether there are pending diff draft sends.
@@ -2126,7 +2138,7 @@
     hasPendingDiffDrafts() {
       const promises = this._pendingRequests[Requests.SEND_DIFF_DRAFT];
       return promises && promises.length;
-    },
+    }
 
     /**
      * @returns {!Promise<undefined>} A promise that resolves when all pending
@@ -2137,7 +2149,7 @@
           .then(() => {
             this._pendingRequests[Requests.SEND_DIFF_DRAFT] = [];
           });
-    },
+    }
 
     _sendDiffDraftRequest(method, changeNum, patchNum, draft) {
       const isCreate = !draft.id && method === 'PUT';
@@ -2173,7 +2185,7 @@
       }
 
       return promise;
-    },
+    }
 
     getCommitInfo(project, commit) {
       return this._restApiHelper.fetchJSON({
@@ -2181,7 +2193,7 @@
             '/commits/' + encodeURIComponent(commit),
         anonymizedUrl: '/projects/*/comments/*',
       });
-    },
+    }
 
     _fetchB64File(url) {
       return this._restApiHelper.fetch({url: this.getBaseUrl() + url})
@@ -2195,7 +2207,7 @@
                   return {body: text, type};
                 });
           });
-    },
+    }
 
     /**
      * @param {string} changeId
@@ -2210,7 +2222,7 @@
         url = `${url}/files/${encodeURIComponent(path)}/content${parent}`;
         return this._fetchB64File(url);
       });
-    },
+    }
 
     getImagesForDiff(changeNum, diff, patchRange) {
       let promiseA;
@@ -2252,7 +2264,7 @@
 
         return {baseImage, revisionImage};
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -2273,7 +2285,7 @@
         }
         return url;
       });
-    },
+    }
 
     /**
      * @suppress {checkTypes}
@@ -2289,7 +2301,7 @@
         parseResponse: true,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @suppress {checkTypes}
@@ -2305,7 +2317,7 @@
         parseResponse: true,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     deleteAccountHttpPassword() {
       return this._restApiHelper.send({
@@ -2313,7 +2325,7 @@
         url: '/accounts/self/password.http',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @suppress {checkTypes}
@@ -2328,14 +2340,14 @@
         parseResponse: true,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     getAccountSSHKeys() {
       return this._fetchSharedCacheURL({
         url: '/accounts/self/sshkeys',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     addAccountSSHKey(key) {
       const req = {
@@ -2356,7 +2368,7 @@
             if (!obj.valid) { return Promise.reject(new Error('error')); }
             return obj;
           });
-    },
+    }
 
     deleteAccountSSHKey(id) {
       return this._restApiHelper.send({
@@ -2364,14 +2376,14 @@
         url: '/accounts/self/sshkeys/' + id,
         anonymizedUrl: '/accounts/self/sshkeys/*',
       });
-    },
+    }
 
     getAccountGPGKeys() {
       return this._restApiHelper.fetchJSON({
         url: '/accounts/self/gpgkeys',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     addAccountGPGKey(key) {
       const req = {
@@ -2391,7 +2403,7 @@
             if (!obj) { return Promise.reject(new Error('error')); }
             return obj;
           });
-    },
+    }
 
     deleteAccountGPGKey(id) {
       return this._restApiHelper.send({
@@ -2399,7 +2411,7 @@
         url: '/accounts/self/gpgkeys/' + id,
         anonymizedUrl: '/accounts/self/gpgkeys/*',
       });
-    },
+    }
 
     deleteVote(changeNum, account, label) {
       return this._getChangeURLAndSend({
@@ -2408,7 +2420,7 @@
         endpoint: `/reviewers/${account}/votes/${encodeURIComponent(label)}`,
         anonymizedEndpoint: '/reviewers/*/votes/*',
       });
-    },
+    }
 
     setDescription(changeNum, patchNum, desc) {
       return this._getChangeURLAndSend({
@@ -2418,7 +2430,7 @@
         body: {description: desc},
         reportUrlAsIs: true,
       });
-    },
+    }
 
     confirmEmail(token) {
       const req = {
@@ -2433,7 +2445,7 @@
         }
         return null;
       });
-    },
+    }
 
     getCapabilities(opt_errFn) {
       return this._restApiHelper.fetchJSON({
@@ -2441,7 +2453,7 @@
         errFn: opt_errFn,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     getTopMenus(opt_errFn) {
       return this._fetchSharedCacheURL({
@@ -2449,7 +2461,7 @@
         errFn: opt_errFn,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     setAssignee(changeNum, assignee) {
       return this._getChangeURLAndSend({
@@ -2459,7 +2471,7 @@
         body: {assignee},
         reportUrlAsIs: true,
       });
-    },
+    }
 
     deleteAssignee(changeNum) {
       return this._getChangeURLAndSend({
@@ -2468,14 +2480,14 @@
         endpoint: '/assignee',
         reportUrlAsIs: true,
       });
-    },
+    }
 
     probePath(path) {
       return fetch(new Request(path, {method: 'HEAD'}))
           .then(response => {
             return response.ok;
           });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -2498,7 +2510,7 @@
           return 'Change marked as Work In Progress.';
         }
       });
-    },
+    }
 
     /**
      * @param {number|string} changeNum
@@ -2514,7 +2526,7 @@
         errFn: opt_errFn,
         reportUrlAsIs: true,
       });
-    },
+    }
 
     /**
      * @suppress {checkTypes}
@@ -2531,7 +2543,7 @@
         parseResponse: true,
         anonymizedEndpoint: '/comments/*/delete',
       });
-    },
+    }
 
     /**
      * Given a changeNum, gets the change.
@@ -2550,7 +2562,7 @@
         if (!res || !res.length) { return null; }
         return res[0];
       });
-    },
+    }
 
     /**
      * @param {string|number} changeNum
@@ -2563,7 +2575,7 @@
             'One of them must be invalid.');
       }
       this._projectLookup[changeNum] = project;
-    },
+    }
 
     /**
      * Checks in _projectLookup for the changeNum. If it exists, returns the
@@ -2587,7 +2599,7 @@
         this.setInProjectLookup(changeNum, change.project);
         return change.project;
       });
-    },
+    }
 
     /**
      * Alias for _changeBaseURL.then(send).
@@ -2614,7 +2626,7 @@
             (anonymizedBaseUrl + anonymizedEndpoint) : undefined,
         });
       });
-    },
+    }
 
     /**
      * Alias for _changeBaseURL.then(_fetchJSON).
@@ -2636,7 +2648,7 @@
             (anonymizedBaseUrl + anonymizedEndpoint) : undefined,
         });
       });
-    },
+    }
 
     /**
      * Execute a change action or revision action on a change.
@@ -2658,7 +2670,7 @@
         body: opt_payload,
         errFn: opt_errFn,
       });
-    },
+    }
 
     /**
      * Get blame information for the given diff.
@@ -2678,7 +2690,7 @@
         params: opt_base ? {base: 't'} : undefined,
         anonymizedEndpoint: '/files/*/blame',
       });
-    },
+    }
 
     /**
      * Modify the given create draft request promise so that it fails and throws
@@ -2707,7 +2719,7 @@
         }
         return result;
       });
-    },
+    }
 
     /**
      * Fetch a project dashboard definition.
@@ -2726,7 +2738,7 @@
         errFn: opt_errFn,
         anonymizedUrl: '/projects/*/dashboards/*',
       });
-    },
+    }
 
     /**
      * @param {string} filter
@@ -2742,7 +2754,7 @@
         url: `/Documentation/?q=${encodedFilter}`,
         anonymizedUrl: '/Documentation/?*',
       });
-    },
+    }
 
     getMergeable(changeNum) {
       return this._getChangeURLAndFetch({
@@ -2751,7 +2763,7 @@
         parseResponse: true,
         reportEndpointAsIs: true,
       });
-    },
+    }
 
     deleteDraftComments(query) {
       return this._restApiHelper.send({
@@ -2759,6 +2771,8 @@
         url: '/accounts/self/drafts:delete',
         body: {query},
       });
-    },
-  });
+    }
+  }
+
+  customElements.define(GrRestApiInterface.is, GrRestApiInterface);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-select/gr-select.js b/polygerrit-ui/app/elements/shared/gr-select/gr-select.js
index 05267ba..152834f 100644
--- a/polygerrit-ui/app/elements/shared/gr-select/gr-select.js
+++ b/polygerrit-ui/app/elements/shared/gr-select/gr-select.js
@@ -17,29 +17,29 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-select',
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    */
+  class GrSelect extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-select'; }
 
-    properties: {
-      bindValue: {
-        type: String,
-        notify: true,
-        observer: '_updateValue',
-      },
-    },
-
-    behaviors: [
-      Gerrit.FireBehavior,
-    ],
-
-    listeners: {
-      'change': '_valueChanged',
-      'dom-change': '_updateValue',
-    },
+    static get properties() {
+      return {
+        bindValue: {
+          type: String,
+          notify: true,
+          observer: '_updateValue',
+        },
+      };
+    }
 
     get nativeSelect() {
       return this.$$('select');
-    },
+    }
 
     _updateValue() {
       // It's possible to have a value of 0.
@@ -53,21 +53,32 @@
           this.nativeSelect.value = this.bindValue;
         }, 1);
       }
-    },
+    }
 
     _valueChanged() {
       this.bindValue = this.nativeSelect.value;
-    },
+    }
 
     focus() {
       this.nativeSelect.focus();
-    },
+    }
+
+    created() {
+      super.created();
+      this.addEventListener('change',
+          () => this._valueChanged());
+      this.addEventListener('dom-change',
+          () => this._updateValue());
+    }
 
     ready() {
+      super.ready();
       // If not set via the property, set bind-value to the element value.
       if (this.bindValue == undefined && this.nativeSelect.options.length > 0) {
         this.bindValue = this.nativeSelect.value;
       }
-    },
-  });
+    }
+  }
+
+  customElements.define(GrSelect.is, GrSelect);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-shell-command/gr-shell-command.js b/polygerrit-ui/app/elements/shared/gr-shell-command/gr-shell-command.js
index 2c546cc..9456991 100644
--- a/polygerrit-ui/app/elements/shared/gr-shell-command/gr-shell-command.js
+++ b/polygerrit-ui/app/elements/shared/gr-shell-command/gr-shell-command.js
@@ -17,16 +17,22 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-shell-command',
+  class GrShellCommand extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-shell-command'; }
 
-    properties: {
-      command: String,
-      label: String,
-    },
+    static get properties() {
+      return {
+        command: String,
+        label: String,
+      };
+    }
 
     focusOnCopy() {
       this.$$('gr-copy-clipboard').focusOnCopy();
-    },
-  });
+    }
+  }
+
+  customElements.define(GrShellCommand.is, GrShellCommand);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-storage/gr-storage.js b/polygerrit-ui/app/elements/shared/gr-storage/gr-storage.js
index f6ade6e..7950e51 100644
--- a/polygerrit-ui/app/elements/shared/gr-storage/gr-storage.js
+++ b/polygerrit-ui/app/elements/shared/gr-storage/gr-storage.js
@@ -28,52 +28,56 @@
     'editablecontent:',
   ];
 
-  Polymer({
-    is: 'gr-storage',
+  class GrStorage extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-storage'; }
 
-    properties: {
-      _lastCleanup: Number,
-      /** @type {?Storage} */
-      _storage: {
-        type: Object,
-        value() {
-          return window.localStorage;
+    static get properties() {
+      return {
+        _lastCleanup: Number,
+        /** @type {?Storage} */
+        _storage: {
+          type: Object,
+          value() {
+            return window.localStorage;
+          },
         },
-      },
-      _exceededQuota: {
-        type: Boolean,
-        value: false,
-      },
-    },
+        _exceededQuota: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
 
     getDraftComment(location) {
       this._cleanupItems();
       return this._getObject(this._getDraftKey(location));
-    },
+    }
 
     setDraftComment(location, message) {
       const key = this._getDraftKey(location);
       this._setObject(key, {message, updated: Date.now()});
-    },
+    }
 
     eraseDraftComment(location) {
       const key = this._getDraftKey(location);
       this._storage.removeItem(key);
-    },
+    }
 
     getEditableContentItem(key) {
       this._cleanupItems();
       return this._getObject(this._getEditableContentKey(key));
-    },
+    }
 
     setEditableContentItem(key, message) {
       this._setObject(this._getEditableContentKey(key),
           {message, updated: Date.now()});
-    },
+    }
 
     eraseEditableContentItem(key) {
       this._storage.removeItem(this._getEditableContentKey(key));
-    },
+    }
 
     _getDraftKey(location) {
       const range = location.range ?
@@ -86,11 +90,11 @@
         key = key + ':' + range;
       }
       return key;
-    },
+    }
 
     _getEditableContentKey(key) {
       return `editablecontent:${key}`;
-    },
+    }
 
     _cleanupItems() {
       // Throttle cleanup to the throttle interval.
@@ -113,13 +117,13 @@
           }
         }
       }
-    },
+    }
 
     _getObject(key) {
       const serial = this._storage.getItem(key);
       if (!serial) { return null; }
       return JSON.parse(serial);
-    },
+    }
 
     _setObject(key, obj) {
       if (this._exceededQuota) { return; }
@@ -136,6 +140,8 @@
           throw exc;
         }
       }
-    },
-  });
+    }
+  }
+
+  customElements.define(GrStorage.is, GrStorage);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.js b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.js
index 4c4b038..5011067 100644
--- a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.js
+++ b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.js
@@ -52,73 +52,81 @@
     {value: '😜', match: 'winking tongue ;)'},
   ];
 
-  Polymer({
-    is: 'gr-textarea',
-
+  /**
+    * @appliesMixin Gerrit.FireMixin
+    * @appliesMixin Gerrit.KeyboardShortcutMixin
+    */
+  class GrTextarea extends Polymer.mixinBehaviors( [
+    Gerrit.FireBehavior,
+    Gerrit.KeyboardShortcutBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-textarea'; }
     /**
      * @event bind-value-changed
      */
 
-    properties: {
-      autocomplete: Boolean,
-      disabled: Boolean,
-      rows: Number,
-      maxRows: Number,
-      placeholder: String,
-      text: {
-        type: String,
-        notify: true,
-        observer: '_handleTextChanged',
-      },
-      hideBorder: {
-        type: Boolean,
-        value: false,
-      },
-      /** Text input should be rendered in monspace font.  */
-      monospace: {
-        type: Boolean,
-        value: false,
-      },
-      /** Text input should be rendered in code font, which is smaller than the
+    static get properties() {
+      return {
+        autocomplete: Boolean,
+        disabled: Boolean,
+        rows: Number,
+        maxRows: Number,
+        placeholder: String,
+        text: {
+          type: String,
+          notify: true,
+          observer: '_handleTextChanged',
+        },
+        hideBorder: {
+          type: Boolean,
+          value: false,
+        },
+        /** Text input should be rendered in monspace font.  */
+        monospace: {
+          type: Boolean,
+          value: false,
+        },
+        /** Text input should be rendered in code font, which is smaller than the
           standard monospace font. */
-      code: {
-        type: Boolean,
-        value: false,
-      },
-      /** @type(?number) */
-      _colonIndex: Number,
-      _currentSearchString: {
-        type: String,
-        observer: '_determineSuggestions',
-      },
-      _hideAutocomplete: {
-        type: Boolean,
-        value: true,
-      },
-      _index: Number,
-      _suggestions: Array,
-      // Offset makes dropdown appear below text.
-      _verticalOffset: {
-        type: Number,
-        value: 20,
-        readOnly: true,
-      },
-    },
+        code: {
+          type: Boolean,
+          value: false,
+        },
+        /** @type(?number) */
+        _colonIndex: Number,
+        _currentSearchString: {
+          type: String,
+          observer: '_determineSuggestions',
+        },
+        _hideAutocomplete: {
+          type: Boolean,
+          value: true,
+        },
+        _index: Number,
+        _suggestions: Array,
+        // Offset makes dropdown appear below text.
+        _verticalOffset: {
+          type: Number,
+          value: 20,
+          readOnly: true,
+        },
+      };
+    }
 
-    behaviors: [
-      Gerrit.FireBehavior,
-      Gerrit.KeyboardShortcutBehavior,
-    ],
-
-    keyBindings: {
-      esc: '_handleEscKey',
-      tab: '_handleEnterByKey',
-      enter: '_handleEnterByKey',
-      up: '_handleUpKey',
-      down: '_handleDownKey',
-    },
+    get keyBindings() {
+      return {
+        esc: '_handleEscKey',
+        tab: '_handleEnterByKey',
+        enter: '_handleEnterByKey',
+        up: '_handleUpKey',
+        down: '_handleDownKey',
+      };
+    }
 
     ready() {
+      super.ready();
       if (this.monospace) {
         this.classList.add('monospace');
       }
@@ -128,15 +136,15 @@
       if (this.hideBorder) {
         this.$.textarea.classList.add('noBorder');
       }
-    },
+    }
 
     closeDropdown() {
       return this.$.emojiSuggestions.close();
-    },
+    }
 
     getNativeTextarea() {
       return this.$.textarea.textarea;
-    },
+    }
 
     putCursorAtEnd() {
       const textarea = this.getNativeTextarea();
@@ -146,14 +154,14 @@
       this.async(() => {
         textarea.focus();
       });
-    },
+    }
 
     _handleEscKey(e) {
       if (this._hideAutocomplete) { return; }
       e.preventDefault();
       e.stopPropagation();
       this._resetEmojiDropdown();
-    },
+    }
 
     _handleUpKey(e) {
       if (this._hideAutocomplete) { return; }
@@ -162,7 +170,7 @@
       this.$.emojiSuggestions.cursorUp();
       this.$.textarea.textarea.focus();
       this.disableEnterKeyForSelectingEmoji = false;
-    },
+    }
 
     _handleDownKey(e) {
       if (this._hideAutocomplete) { return; }
@@ -171,7 +179,7 @@
       this.$.emojiSuggestions.cursorDown();
       this.$.textarea.textarea.focus();
       this.disableEnterKeyForSelectingEmoji = false;
-    },
+    }
 
     _handleEnterByKey(e) {
       if (this._hideAutocomplete || this.disableEnterKeyForSelectingEmoji) {
@@ -180,11 +188,11 @@
       e.preventDefault();
       e.stopPropagation();
       this._setEmoji(this.$.emojiSuggestions.getCurrentText());
-    },
+    }
 
     _handleEmojiSelect(e) {
       this._setEmoji(e.detail.selected.dataset.value);
-    },
+    }
 
     _setEmoji(text) {
       const colonIndex = this._colonIndex;
@@ -193,12 +201,13 @@
       this.$.textarea.selectionEnd = colonIndex + 1;
       this.$.reporting.reportInteraction('select-emoji');
       this._resetEmojiDropdown();
-    },
+    }
 
     _getText(value) {
       return this.text.substr(0, this._colonIndex || 0) +
           value + this.text.substr(this.$.textarea.selectionStart);
-    },
+    }
+
     /**
      * Uses a hidden element with the same width and styling of the textarea and
      * the text up until the point of interest. Then caratSpan element is added
@@ -214,17 +223,17 @@
       this.$.hiddenText.appendChild(caratSpan);
       this.$.emojiSuggestions.positionTarget = caratSpan;
       this._openEmojiDropdown();
-    },
+    }
 
     _getFontSize() {
       const fontSizePx = getComputedStyle(this).fontSize || '12px';
       return parseInt(fontSizePx.substr(0, fontSizePx.length - 2),
           10);
-    },
+    }
 
     _getScrollTop() {
       return document.body.scrollTop;
-    },
+    }
 
     /**
      * _handleKeydown used for key handling in the this.$.textarea AND all child
@@ -271,12 +280,12 @@
         this._updateCaratPosition();
       }
       this.$.textarea.textarea.focus();
-    },
+    }
 
     _openEmojiDropdown() {
       this.$.emojiSuggestions.open();
       this.$.reporting.reportInteraction('open-emoji-dropdown');
-    },
+    }
 
     _formatSuggestions(matchedSuggestions) {
       const suggestions = [];
@@ -286,7 +295,7 @@
         suggestions.push(suggestion);
       }
       this.set('_suggestions', suggestions);
-    },
+    }
 
     _determineSuggestions(emojiText) {
       if (!emojiText.length) {
@@ -299,7 +308,7 @@
         this._formatSuggestions(matches);
         this.disableEnterKeyForSelectingEmoji = false;
       }
-    },
+    }
 
     _resetEmojiDropdown() {
       // hide and reset the autocomplete dropdown.
@@ -309,11 +318,13 @@
       this.closeDropdown();
       this._colonIndex = null;
       this.$.textarea.textarea.focus();
-    },
+    }
 
     _handleTextChanged(text) {
       this.dispatchEvent(
           new CustomEvent('value-changed', {detail: {value: text}}));
-    },
-  });
+    }
+  }
+
+  customElements.define(GrTextarea.is, GrTextarea);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-tooltip-content/gr-tooltip-content.js b/polygerrit-ui/app/elements/shared/gr-tooltip-content/gr-tooltip-content.js
index c5de8f4..3559949 100644
--- a/polygerrit-ui/app/elements/shared/gr-tooltip-content/gr-tooltip-content.js
+++ b/polygerrit-ui/app/elements/shared/gr-tooltip-content/gr-tooltip-content.js
@@ -17,31 +17,38 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-tooltip-content',
+  /**
+    * @appliesMixin Gerrit.TooltipMixin
+    */
+  class GrTooltipContent extends Polymer.mixinBehaviors( [
+    Gerrit.TooltipBehavior,
+  ], Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element))) {
+    static get is() { return 'gr-tooltip-content'; }
 
-    properties: {
-      title: {
-        type: String,
-        reflectToAttribute: true,
-      },
-      maxWidth: {
-        type: String,
-        reflectToAttribute: true,
-      },
-      positionBelow: {
-        type: Boolean,
-        valye: false,
-        reflectToAttribute: true,
-      },
-      showIcon: {
-        type: Boolean,
-        value: false,
-      },
-    },
+    static get properties() {
+      return {
+        title: {
+          type: String,
+          reflectToAttribute: true,
+        },
+        maxWidth: {
+          type: String,
+          reflectToAttribute: true,
+        },
+        positionBelow: {
+          type: Boolean,
+          valye: false,
+          reflectToAttribute: true,
+        },
+        showIcon: {
+          type: Boolean,
+          value: false,
+        },
+      };
+    }
+  }
 
-    behaviors: [
-      Gerrit.TooltipBehavior,
-    ],
-  });
+  customElements.define(GrTooltipContent.is, GrTooltipContent);
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-tooltip/gr-tooltip.js b/polygerrit-ui/app/elements/shared/gr-tooltip/gr-tooltip.js
index fb87b558..170a442 100644
--- a/polygerrit-ui/app/elements/shared/gr-tooltip/gr-tooltip.js
+++ b/polygerrit-ui/app/elements/shared/gr-tooltip/gr-tooltip.js
@@ -17,23 +17,29 @@
 (function() {
   'use strict';
 
-  Polymer({
-    is: 'gr-tooltip',
+  class GrTooltip extends Polymer.GestureEventListeners(
+      Polymer.LegacyElementMixin(
+          Polymer.Element)) {
+    static get is() { return 'gr-tooltip'; }
 
-    properties: {
-      text: String,
-      maxWidth: {
-        type: String,
-        observer: '_updateWidth',
-      },
-      positionBelow: {
-        type: Boolean,
-        reflectToAttribute: true,
-      },
-    },
+    static get properties() {
+      return {
+        text: String,
+        maxWidth: {
+          type: String,
+          observer: '_updateWidth',
+        },
+        positionBelow: {
+          type: Boolean,
+          reflectToAttribute: true,
+        },
+      };
+    }
 
     _updateWidth(maxWidth) {
       this.updateStyles({'--tooltip-max-width': maxWidth});
-    },
-  });
+    }
+  }
+
+  customElements.define(GrTooltip.is, GrTooltip);
 })();