diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
index 765b49d..8c6536a 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
@@ -351,7 +351,9 @@
     },
 
     _getListItems() {
-      return Polymer.dom(this.root).querySelectorAll('gr-change-list-item');
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      return Array.from(
+          Polymer.dom(this.root).querySelectorAll('gr-change-list-item'));
     },
 
     _sectionsChanged() {
diff --git a/polygerrit-ui/app/elements/change/gr-account-list/gr-account-list.js b/polygerrit-ui/app/elements/change/gr-account-list/gr-account-list.js
index 950c1e8..cf2f0e5 100644
--- a/polygerrit-ui/app/elements/change/gr-account-list/gr-account-list.js
+++ b/polygerrit-ui/app/elements/change/gr-account-list/gr-account-list.js
@@ -88,7 +88,9 @@
     },
 
     get accountChips() {
-      return Polymer.dom(this.root).querySelectorAll('gr-account-chip');
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      return Array.from(
+          Polymer.dom(this.root).querySelectorAll('gr-account-chip'));
     },
 
     get focusStart() {
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
index 460512a..134920b 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
@@ -291,7 +291,9 @@
     },
 
     get diffs() {
-      return Polymer.dom(this.root).querySelectorAll('gr-diff-host');
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      return Array.from(
+          Polymer.dom(this.root).querySelectorAll('gr-diff-host'));
     },
 
     openDiffPrefs() {
@@ -858,7 +860,9 @@
 
     _filesChanged() {
       Polymer.dom.flush();
-      const files = Polymer.dom(this.root).querySelectorAll('.file-row');
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      const files = Array.from(
+          Polymer.dom(this.root).querySelectorAll('.file-row'));
       this.$.fileCursor.stops = files;
       this.$.fileCursor.setCursorAtIndex(this.selectedIndex, true);
     },
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
index 65c8233..9e6314dd 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
@@ -340,7 +340,9 @@
      * @return {!Array<!HTMLElement>}
      */
     getThreadEls() {
-      return Polymer.dom(this.$.diff).querySelectorAll('.comment-thread');
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      return Array.from(
+          Polymer.dom(this.$.diff).querySelectorAll('.comment-thread'));
     },
 
     /** @param {HTMLElement} el */
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
index 2146d9d..045a8e3 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
@@ -406,7 +406,9 @@
         return [];
       }
 
-      return Polymer.dom(this.root).querySelectorAll('.diff-row');
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      return Array.from(
+          Polymer.dom(this.root).querySelectorAll('.diff-row'));
     },
 
     /** @return {boolean} */
diff --git a/polygerrit-ui/app/elements/plugins/gr-endpoint-decorator/gr-endpoint-decorator.js b/polygerrit-ui/app/elements/plugins/gr-endpoint-decorator/gr-endpoint-decorator.js
index fe82f2b..96bcd5c 100644
--- a/polygerrit-ui/app/elements/plugins/gr-endpoint-decorator/gr-endpoint-decorator.js
+++ b/polygerrit-ui/app/elements/plugins/gr-endpoint-decorator/gr-endpoint-decorator.js
@@ -71,7 +71,9 @@
     },
 
     _getEndpointParams() {
-      return Polymer.dom(this).querySelectorAll('gr-endpoint-param');
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      return Array.from(
+          Polymer.dom(this).querySelectorAll('gr-endpoint-param'));
     },
 
     /**
diff --git a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.js b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.js
index 7d109633..43afdf8 100644
--- a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.js
+++ b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.js
@@ -41,8 +41,9 @@
      * @return {!Array<string>}
      */
     _getDisplayedColumns() {
-      return Polymer.dom(this.root)
-          .querySelectorAll('.checkboxContainer input:not([name=number])')
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      return Array.from(Polymer.dom(this.root)
+          .querySelectorAll('.checkboxContainer input:not([name=number])'))
           .filter(checkbox => checkbox.checked)
           .map(checkbox => checkbox.name);
     },
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 2e55010..fb2c182 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
@@ -162,7 +162,9 @@
     _resetCursorStops() {
       if (this.suggestions.length > 0) {
         Polymer.dom.flush();
-        this._suggestionEls = this.$.suggestions.querySelectorAll('li');
+        // Polymer2: querySelectorAll returns NodeList instead of Array.
+        this._suggestionEls = Array.from(
+            this.$.suggestions.querySelectorAll('li'));
       } else {
         this._suggestionEls = [];
       }
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 3d9d36b..969272f 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js
@@ -280,7 +280,9 @@
      */
     _resetCursorStops() {
       Polymer.dom.flush();
-      this._listElements = Polymer.dom(this.root).querySelectorAll('li');
+      // Polymer2: querySelectorAll returns NodeList instead of Array.
+      this._listElements = Array.from(
+          Polymer.dom(this.root).querySelectorAll('li'));
     },
 
     _computeHasTooltip(tooltip) {