DevTools: Fix timeline overview popover sticking at last

third_party/WebKit/Source/devtools/front_end/perf_ui/TimelineOverviewPane.js

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 52 matching lines @@
 
   /**
    * @param {!Event} event
    */
   _onMouseMove(event) {
     if (!this._cursorEnabled)
       return;
     this._cursorPosition = event.offsetX + event.target.offsetLeft;
     this._cursorElement.style.left = this._cursorPosition + 'px';
     this._cursorElement.style.visibility = 'visible';
-    this._buildOverviewInfo().then(content => this._overviewInfo.setContent(content));
+    this._overviewInfo.setContent(this._buildOverviewInfo());
   }
 
   /**
    * @return {!Promise<!DocumentFragment>}
    */
   async _buildOverviewInfo() {
     var document = this.element.ownerDocument;
     var x = this._cursorPosition;
     var elements = await Promise.all(this._overviewControls.map(control => control.overviewInfoPromise(x)));
     var fragment = document.createDocumentFragment();
@@ skipping 391 matching lines @@
 PerfUI.TimelineOverviewPane.OverviewInfo = class {
   /**
    * @param {!Element} anchor
    */
   constructor(anchor) {
     this._anchorElement = anchor;
     this._glassPane = new UI.GlassPane();
     this._glassPane.setPointerEventsBehavior(UI.GlassPane.PointerEventsBehavior.PierceContents);
     this._glassPane.setMarginBehavior(UI.GlassPane.MarginBehavior.Arrow);
     this._glassPane.setSizeBehavior(UI.GlassPane.SizeBehavior.MeasureContent);
+    this._visible = false;
     this._element =
         UI.createShadowRootWithCoreStyles(this._glassPane.contentElement, 'perf_ui/timelineOverviewInfo.css')
             .createChild('div', 'overview-info');
   }
 
   /**
-   * @param {!DocumentFragment} content
+   * @param {!Promise<!DocumentFragment>} contentPromise
    */
-  setContent(content) {
+  async setContent(contentPromise) {
+    this._visible = true;
+    var content = await contentPromise;
+    if (!this._visible)
+      return;
     this._element.removeChildren();
     this._element.appendChild(content);
     this._glassPane.setContentAnchorBox(this._anchorElement.boxInWindow());
     if (!this._glassPane.isShowing())
       this._glassPane.show(/** @type {!Document} */ (this._anchorElement.ownerDocument));
   }
 
   hide() {
+    this._visible = false;
     this._glassPane.hide();
   }
 };