[DevTools] Replace usages of document with custom functions.

Source/devtools/front_end/layers/LayerTreeOutline.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 167 matching lines @@
 WebInspector.LayerTreeElement = function(tree, layer)
 {
     TreeElement.call(this, "", layer);
     this._treeOutline = tree;
     this._update();
 }
 
 WebInspector.LayerTreeElement.prototype = {
     onattach: function()
     {
-        var selection = document.createElement("div");
+        var selection = createElement("div");
         selection.className = "selection";
         this.listItemElement.insertBefore(selection, this.listItemElement.firstChild);
     },
 
     _update: function()
     {
         var layer = /** @type {!WebInspector.Layer} */ (this.representedObject);
         var node = layer.nodeForSelfOrAncestor();
-        var title = document.createDocumentFragment();
+        var title = createDocumentFragment();
         title.createChild("div", "selection");
         title.createTextChild(node ? WebInspector.DOMPresentationUtils.simpleSelector(node) : "#" + layer.id());
         var details = title.createChild("span", "dimmed");
         details.textContent = WebInspector.UIString(" (%d × %d)", layer.width(), layer.height());
         this.title = title;
     },
 
     /**
      * @override
      * @return {boolean}
      */
     onselect: function()
     {
         this._treeOutline._selectedNodeChanged(this);
         return false;
     },
 
     /**
      * @param {boolean} hovered
      */
     setHovered: function(hovered)
     {
         this.listItemElement.classList.toggle("hovered", hovered);
     },
 
     __proto__: TreeElement.prototype
 }