DevTools: fix deepActiveElement and focus on Dialog when document blurs

third_party/WebKit/Source/devtools/front_end/platform/DOMExtension.js

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 914 matching lines @@
         node = node.shadowRoot.elementFromPoint(this.pageX, this.pageY);
     return node;
 }
 
 /**
  * @return {?Element}
  */
 Event.prototype.deepActiveElement = function()
 {
     var activeElement = this.target && this.target.ownerDocument ? this.target.ownerDocument.activeElement : null;
-    while (activeElement && activeElement.shadowRoot)
+    while (activeElement && activeElement.shadowRoot && activeElement.shadowRoot.activeElement)
         activeElement = activeElement.shadowRoot.activeElement;
     return activeElement;
 }
 
 /**
  * @param {number} x
  * @param {number} y
  * @return {?Node}
  */
 Document.prototype.deepElementFromPoint = function(x, y)
@@ skipping 41 matching lines @@
     {
         window.removeEventListener("DOMContentLoaded", windowLoaded, false);
         callback();
     }
 
     if (document.readyState === "complete" || document.readyState === "interactive")
         callback();
     else
         window.addEventListener("DOMContentLoaded", windowLoaded, false);
 }