DevTools: fix author shadow dom inspection mode, speacial-case ua. Fix crash from the bug.

Source/devtools/front_end/ElementsTreeOutline.js

 /*
  * Copyright (C) 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2008 Matt Lilek <webkit@mattlilek.com>
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * 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
@@ skipping 2399 matching lines @@
         
         WebInspector.RemoteObject.resolveNode(this._node, "", scrollIntoViewCallback);
     },
 
     /**
      * @return {!Array.<!WebInspector.DOMAgent>}
      */
     _visibleShadowRoots: function()
     {
         var roots = this._node.shadowRoots();
-        if (roots.length && !WebInspector.settings.showShadowDOM.get()) {
+        if (roots.length && !WebInspector.settings.showUAShadowDOM.get()) {
             roots = roots.filter(function(root) {
                 return root.shadowRootType() === WebInspector.DOMNode.ShadowRootTypes.Author;
             });
         }
         return roots;
     },
 
     /**
      * @return {!Array.<!WebInspector.DOMNode>} visibleChildren
      */
@@ skipping 227 matching lines @@
         var treeOutline = new WebInspector.ElementsTreeOutline(false, false);
         treeOutline.rootDOMNode = /** @type {!WebInspector.DOMNode} */ (object);
         treeOutline.element.classList.add("outline-disclosure");
         if (!treeOutline.children[0].hasChildren)
             treeOutline.element.classList.add("single-node");
         treeOutline.setVisible(true);
         treeOutline.element.treeElementForTest = treeOutline.children[0];
         return treeOutline.element;
     }
 }