Makes Embed() take a single node

mojo/services/view_manager/test_change_tracker.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SERVICES_VIEW_MANAGER_TEST_CHANGE_TRACKER_H_
 #define MOJO_SERVICES_VIEW_MANAGER_TEST_CHANGE_TRACKER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 83 matching lines @@
   void set_delegate(Delegate* delegate) { delegate_ = delegate; }
 
   std::vector<Change>* changes() { return &changes_; }
 
   // Each of these functions generate a Change. There is one per
   // ViewManagerClient function.
   void OnViewManagerConnectionEstablished(ConnectionSpecificId connection_id,
                                           const String& creator_url,
                                           Id next_server_change_id,
                                           Array<NodeDataPtr> nodes);
-  void OnRootsAdded(Array<NodeDataPtr> nodes);
+  void OnRootAdded(Array<NodeDataPtr> nodes);
   void OnServerChangeIdAdvanced(Id change_id);
   void OnNodeBoundsChanged(Id node_id, RectPtr old_bounds, RectPtr new_bounds);
   void OnNodeHierarchyChanged(Id node_id,
                               Id new_parent_id,
                               Id old_parent_id,
                               Id server_change_id,
                               Array<NodeDataPtr> nodes);
   void OnNodeReordered(Id node_id,
                        Id relative_node_id,
                        OrderDirection direction,
@@ skipping 10 matching lines @@
   std::vector<Change> changes_;
 
   DISALLOW_COPY_AND_ASSIGN(TestChangeTracker);
 };
 
 }  // namespace service
 }  // namespace view_manager
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_VIEW_MANAGER_TEST_CHANGE_TRACKER_H_