Remove pinned header behavior

Change-Id: Ida1a4678983a100a34ca8b441dfe58108807f2e8
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
index e3f7fd2..cde8929b 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
@@ -45,14 +45,9 @@
         color: #666;
         padding: 1em var(--default-horizontal-margin);
       }
-      .headerContainer {
-        height: 4.1em;
-        margin-bottom: .5em;
-      }
       .header {
         align-items: center;
         background-color: var(--view-background-color);
-        border-bottom: 1px solid #ddd;
         display: flex;
         padding: 1em var(--default-horizontal-margin);
         z-index: 99;  /* Less than gr-overlay's backdrop */
@@ -149,9 +144,6 @@
         padding: 0 var(--default-horizontal-margin);
       }
       @media screen and (max-width: 50em) {
-        .headerContainer {
-          height: 5.15em;
-        }
         .header {
           align-items: flex-start;
           flex-direction: column;
@@ -215,36 +207,35 @@
     </style>
     <div class="container loading" hidden$="{{!_loading}}">Loading...</div>
     <div class="container" hidden$="{{_loading}}">
-      <div class="headerContainer">
-        <div class="header">
-          <span class="header-title">
-            <gr-change-star change="{{_change}}" hidden$="[[!_loggedIn]]"></gr-change-star>
-            <a href$="[[_computeChangePermalink(_change._number)]]">[[_change._number]]</a><span>:</span>
-            <span>[[_change.subject]]</span>
-            <span class="changeStatus">[[_computeChangeStatus(_change, _patchRange.patchNum)]]</span>
+      <div class="header">
+        <span class="header-title">
+          <gr-change-star change="{{_change}}" hidden$="[[!_loggedIn]]"></gr-change-star>
+          <a href$="[[_computeChangePermalink(_change._number)]]">[[_change._number]]</a><span>:</span>
+          <span>[[_change.subject]]</span>
+          <span class="changeStatus">[[_computeChangeStatus(_change, _patchRange.patchNum)]]</span>
+        </span>
+        <span class="header-actions">
+          <gr-button hidden
+              class="reply"
+              primary$="[[_computeReplyButtonHighlighted(_diffDrafts.*)]]"
+              hidden$="[[!_loggedIn]]"
+              on-tap="_handleReplyTap">[[_replyButtonLabel]]</gr-button>
+          <gr-button class="download" on-tap="_handleDownloadTap">Download</gr-button>
+          <span>
+            <label class="patchSelectLabel" for="patchSetSelect">Patch set</label>
+            <select id="patchSetSelect" on-change="_handlePatchChange">
+              <template is="dom-repeat" items="{{_allPatchSets}}" as="patchNumber">
+                <option value$="[[patchNumber]]" selected$="[[_computePatchIndexIsSelected(index, _patchRange.patchNum)]]">
+                  <span>[[patchNumber]]</span>
+                  /
+                  <span>[[_computeLatestPatchNum(_allPatchSets)]]</span>
+                </option>
+              </template>
+            </select>
           </span>
-          <span class="header-actions">
-            <gr-button hidden
-                class="reply"
-                primary$="[[_computeReplyButtonHighlighted(_diffDrafts.*)]]"
-                hidden$="[[!_loggedIn]]"
-                on-tap="_handleReplyTap">[[_replyButtonLabel]]</gr-button>
-            <gr-button class="download" on-tap="_handleDownloadTap">Download</gr-button>
-            <span>
-              <label class="patchSelectLabel" for="patchSetSelect">Patch set</label>
-              <select id="patchSetSelect" on-change="_handlePatchChange">
-                <template is="dom-repeat" items="{{_allPatchSets}}" as="patchNumber">
-                  <option value$="[[patchNumber]]" selected$="[[_computePatchIndexIsSelected(index, _patchRange.patchNum)]]">
-                    <span>[[patchNumber]]</span>
-                    /
-                    <span>[[_computeLatestPatchNum(_allPatchSets)]]</span>
-                  </option>
-                </template>
-              </select>
-            </span>
-          </span>
-        </div>
+        </span>
       </div>
+
       <section class="changeInfo">
         <div class="changeInfo-column changeMetadata">
           <gr-change-metadata
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index 84644da..e8516e2 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -78,8 +78,6 @@
         value: false,
       },
       _loading: Boolean,
-      _headerContainerEl: Object,
-      _headerEl: Object,
       _projectConfig: Object,
       _replyButtonLabel: {
         type: String,
@@ -98,10 +96,6 @@
       '_paramsAndChangeChanged(params, _change)',
     ],
 
-    ready: function() {
-      this._headerEl = this.$$('.header');
-    },
-
     attached: function() {
       this._getLoggedIn().then(function(loggedIn) {
         this._loggedIn = loggedIn;
@@ -114,34 +108,6 @@
           this._handleCommitMessageSave.bind(this));
       this.addEventListener('editable-content-cancel',
           this._handleCommitMessageCancel.bind(this));
-      this.listen(window, 'scroll', '_handleBodyScroll');
-    },
-
-    detached: function() {
-      this.unlisten(window, 'scroll', '_handleBodyScroll');
-    },
-
-    _handleBodyScroll: function(e) {
-      var containerEl = this._headerContainerEl ||
-          this.$$('.headerContainer');
-
-      // Calculate where the header is relative to the window.
-      var top = containerEl.offsetTop;
-      for (var offsetParent = containerEl.offsetParent;
-           offsetParent;
-           offsetParent = offsetParent.offsetParent) {
-        top += offsetParent.offsetTop;
-      }
-      // The element may not be displayed yet, in which case do nothing.
-      if (top == 0) { return; }
-
-      this._headerEl.classList.toggle('pinned', window.scrollY >= top);
-    },
-
-    _resetHeaderEl: function() {
-      var el = this._headerEl || this.$$('.header');
-      this._headerEl = el;
-      el.classList.remove('pinned');
     },
 
     _handleEditCommitMessage: function(e) {
@@ -327,9 +293,6 @@
       };
 
       this._reload().then(function() {
-        this.$.messageList.topMargin = this._headerEl.offsetHeight;
-        this.$.fileList.topMargin = this._headerEl.offsetHeight;
-
         // Allow the message list to render before scrolling.
         this.async(function() {
           this._maybeScrollToMessage();
@@ -640,8 +603,6 @@
         ]);
       }.bind(this);
 
-      this._resetHeaderEl();
-
       if (this._patchRange.patchNum) {
         return reloadPatchNumDependentResources().then(function() {
           return detailCompletes;