[DevTools] Continue GlassPane refactoring.

third_party/WebKit/Source/devtools/front_end/dom_extension/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 740 matching lines @@
   var root = this.target && this.target.getComponentRoot();
   return root ? root.deepElementFromPoint(this.pageX, this.pageY) : null;
 };
 
 /**
  * @param {number} x
  * @param {number} y
  * @return {?Node}
  */
 Document.prototype.deepElementFromPoint = function(x, y) {
-  var node = this.elementFromPoint(x, y);
-  while (node && node.shadowRoot)
-    node = node.shadowRoot.elementFromPoint(x, y);
+  var container = this;
+  var node = null;
+  while (container) {
+    var innerNode = container.elementFromPoint(x, y);
+    if (!innerNode)
+      break;
+    node = innerNode;
+    container = node.shadowRoot;
+  }
   return node;
 };
 
 DocumentFragment.prototype.deepElementFromPoint = Document.prototype.deepElementFromPoint;
 
 /**
  * @return {?Element}
  */
 Document.prototype.deepActiveElement = function() {
   var activeElement = this.activeElement;
@@ skipping 31 matching lines @@
   return event.keyCode !== 229 && event.key === 'Enter';
 }
 
 /**
  * @param {!Event} event
  * @return {boolean}
  */
 function isEscKey(event) {
   return event.keyCode === 27;
 }