[DevTools] Replace usages of document with custom functions.

Source/devtools/front_end/components/HelpScreen.js

 /*
  * Copyright (C) 2010 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 42 matching lines @@
 }
 
 /**
  * @type {?WebInspector.HelpScreen}
  */
 WebInspector.HelpScreen._visibleScreen = null;
 
 WebInspector.HelpScreen.prototype = {
     _createCloseButton: function()
     {
-        var closeButton = document.createElement("div");
+        var closeButton = createElement("div");
         closeButton.className = "help-close-button close-button-gray";
         closeButton.addEventListener("click", this.hide.bind(this), false);
         return closeButton;
     },
 
     showModal: function()
     {
         var visibleHelpScreen = WebInspector.HelpScreen._visibleScreen;
         if (visibleHelpScreen === this)
             return;
@@ skipping 71 matching lines @@
     var p = this.contentElement.createChild("p");
     p.classList.add("help-section");
     p.textContent = WebInspector.UIString("Inspected worker has terminated. Once it restarts we will attach to it automatically.");
 }
 
 WebInspector.WorkerTerminatedScreen.prototype = {
 
     __proto__: WebInspector.HelpScreen.prototype
 }