[DevTools] Replace usages of document with custom functions.

Source/devtools/front_end/ui/DropDownMenu.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @extends {WebInspector.Object}
  */
 WebInspector.DropDownMenu = function()
 {
-    this.element = document.createElementWithClass("select", "drop-down-menu");
+    this.element = createElementWithClass("select", "drop-down-menu");
     this.element.addEventListener("mousedown", this._onBeforeMouseDown.bind(this), true);
     this.element.addEventListener("mousedown", consumeEvent, false);
     this.element.addEventListener("change", this._onChange.bind(this), false);
 }
 
 WebInspector.DropDownMenu.Events = {
     BeforeShow: "BeforeShow",
     ItemSelected: "ItemSelected"
 }
 
@@ skipping 37 matching lines @@
         this.element.selectedIndex = -1;
     },
 
     clear: function()
     {
         this.element.removeChildren();
     },
 
     __proto__: WebInspector.Object.prototype
 }