DevTools: zoom frames upon double click, iterate over frames using arrows.

Source/devtools/front_end/ui/Dialog.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 125 matching lines @@
         }
     }
 };
 
 /**
  * @constructor
  * @extends {WebInspector.Object}
  */
 WebInspector.DialogDelegate = function()
 {
-    /** @type {!Element} */
-    this.element;
+    this.element = createElement("div");
 }
 
 WebInspector.DialogDelegate.prototype = {
     /**
      * @param {!Element} element
      */
     show: function(element)
     {
         element.appendChild(this.element);
         this.element.classList.add("dialog-contents");
@@ skipping 48 matching lines @@
 {
     return WebInspector.Dialog._modalHostView;
 };
 
 WebInspector.Dialog.modalHostRepositioned = function()
 {
     if (WebInspector.Dialog._instance)
         WebInspector.Dialog._instance._position();
 };