[DevTools] Turn WebInspector.Panel into a web component.

third_party/WebKit/Source/devtools/front_end/extensions/ExtensionPanel.js

 /*
  * Copyright (C) 2012 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 21 matching lines @@
  * @constructor
  * @implements {WebInspector.Searchable}
  * @extends {WebInspector.Panel}
  * @param {!WebInspector.ExtensionServer} server
  * @param {string} panelName
  * @param {string} id
  * @param {string} pageURL
  */
 WebInspector.ExtensionPanel = function(server, panelName, id, pageURL)
 {
-    WebInspector.Panel.call(this, panelName);
+    WebInspector.Panel.call(this, panelName, true);
     this._server = server;
     this._id = id;
     this.setHideOnDetach();
-    this._panelToolbar = new WebInspector.Toolbar("hidden", this.element);
+    this._panelToolbar = new WebInspector.Toolbar("hidden", this.contentElement);
 
     this._searchableView = new WebInspector.SearchableView(this);
-    this._searchableView.show(this.element);
+    this._searchableView.show(this.contentElement);
 
     var extensionView = new WebInspector.ExtensionView(server, this._id, pageURL, "extension");
     extensionView.show(this._searchableView.element);
 }
 
 WebInspector.ExtensionPanel.prototype = {
     /**
      * @param {!WebInspector.ToolbarItem} item
      */
     addToolbarItem: function(item)
@@ skipping 240 matching lines @@
         if (!title)
             section.titleLessMode();
         section.expand();
         section.editable = false;
         this._objectPropertiesView.element.appendChild(section.element);
         callback();
     },
 
     __proto__: WebInspector.SimpleView.prototype
 }