Devtools: make DOM traversal utilities climb shadow tree.

Source/devtools/front_end/ui/treeoutline.js

 /*
  * Copyright (C) 2007 Apple 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.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 305 matching lines @@
     return this.getCachedTreeElement(representedObject);
 }
 
 /**
  * @param {number} x
  * @param {number} y
  * @return {?TreeElement}
  */
 TreeOutline.prototype.treeElementFromPoint = function(x, y)
 {
-    var node = this._childrenListNode.ownerDocument.elementFromPoint(x, y);
+    var node = this._childrenListNode.ownerDocument.deepElementFromPoint(x, y);
     if (!node)
         return null;
 
     var listNode = node.enclosingNodeOrSelfWithNodeNameInArray(["ol", "li"]);
     if (listNode)
         return listNode.parentTreeElement || listNode.treeElement;
     return null;
 }
 
+/**
+ * @param {?Event} event
+ * @return {?TreeElement}
+ */
+TreeOutline.prototype.treeElementFromEvent = function(event)
+{
+    return event ? this.treeElementFromPoint(event.pageX, event.pageY) : null;
+}
+
 TreeOutline.prototype._treeKeyDown = function(event)
 {
     if (event.target !== this._childrenListNode)
         return;
 
     if (!this.selectedTreeElement || event.shiftKey || event.metaKey || event.ctrlKey)
         return;
 
     var handled = false;
     var nextSelectedElement;
@@ skipping 660 matching lines @@
  * @return {boolean}
  */
 TreeElement.prototype.isEventWithinDisclosureTriangle = function(event)
 {
     // FIXME: We should not use getComputedStyle(). For that we need to get rid of using ::before for disclosure triangle. (http://webk.it/74446)
     var paddingLeftValue = window.getComputedStyle(this._listItemNode).getPropertyCSSValue("padding-left");
     var computedLeftPadding = paddingLeftValue ? paddingLeftValue.getFloatValue(CSSPrimitiveValue.CSS_PX) : 0;
     var left = this._listItemNode.totalOffsetLeft() + computedLeftPadding;
     return event.pageX >= left && event.pageX <= left + this.arrowToggleWidth && this.hasChildren;
 }