DevTools: do not allow using 'this' before call into super.

third_party/WebKit/Source/devtools/front_end/elements/ElementsPanel.js

 /*
  * Copyright (C) 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2008 Matt Lilek <webkit@mattlilek.com>
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 871 matching lines @@
                 showMetrics.call(this, true);
             else if (tabId === WebInspector.UIString("Styles"))
                 showMetrics.call(this, false);
         }
 
         this.sidebarPaneView = WebInspector.viewManager.createTabbedLocation(() => WebInspector.viewManager.showView("elements"));
         var tabbedPane = this.sidebarPaneView.tabbedPane();
         tabbedPane.element.addEventListener("contextmenu", this._sidebarContextMenuEventFired.bind(this), false);
         if (this._popoverHelper)
             this._popoverHelper.hidePopover();
-        this._popoverHelper = new WebInspector.PopoverHelper(tabbedPane.element, this._getPopoverAnchor.bind(this), this._showPopover.bind(this));
+        this._popoverHelper = new WebInspector.PopoverHelper(tabbedPane.element);
+        this._popoverHelper.initializeCallbacks(this._getPopoverAnchor.bind(this), this._showPopover.bind(this));
         this._popoverHelper.setTimeout(0);
 
         if (horizontally) {
             // Styles and computed are merged into a single tab.
             this._splitWidget.installResizer(tabbedPane.headerElement());
 
             var stylesView = new WebInspector.SimpleView(WebInspector.UIString("Styles"));
             stylesView.element.classList.add("flex-auto");
 
             var splitWidget = new WebInspector.SplitWidget(true, true, "stylesPaneSplitViewState", 215);
@@ skipping 217 matching lines @@
     /**
      * @override
      * @param {!WebInspector.DOMNode} node
      * @return {?{title: string, color: string}}
      */
     decorate: function(node)
     {
         return { color: "orange", title: WebInspector.UIString("Element state: %s", ":" + WebInspector.CSSModel.fromNode(node).pseudoState(node).join(", :")) };
     }
 };