[DevTools] Replace usages of document with custom functions.

Source/devtools/front_end/network/RequestHTMLView.js

 /*
  * Copyright (C) 2011 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 39 matching lines @@
     willHide: function(parentElement)
     {
         this.element.removeChildren();
     },
 
     _createIFrame: function()
     {
         // We need to create iframe again each time because contentDocument
         // is deleted when iframe is removed from its parent.
         this.element.removeChildren();
-        var iframe = document.createElement("iframe");
+        var iframe = createElement("iframe");
         iframe.setAttribute("sandbox", ""); // Forbid to run JavaScript and set unique origin.
         iframe.setAttribute("src", this._dataURL);
         this.element.appendChild(iframe);
     },
 
     __proto__: WebInspector.RequestView.prototype
 }