Add EmbedRoot to ViewManagerService.

mojo/services/view_manager/view_manager_service_impl.cc

 // 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.
 
 #include "mojo/services/view_manager/view_manager_service_impl.h"
 
 #include "base/bind.h"
 #include "mojo/services/public/cpp/geometry/geometry_type_converters.h"
 #include "mojo/services/public/cpp/input_events/input_events_type_converters.h"
 #include "mojo/services/view_manager/node.h"
@@ skipping 708 matching lines @@
     DCHECK(node);
     node->SetVisible(visible);
   }
   // TODO(sky): need to notify of visibility changes.
   callback.Run(success);
 }
 
 void ViewManagerServiceImpl::Embed(const String& url,
                                    Id transport_node_id,
                                    const Callback<void(bool)>& callback) {
+  if (NodeIdFromTransportId(transport_node_id) == InvalidNodeId()) {
+    root_node_manager_->EmbedRoot(url);
+    callback.Run(true);
+    return;
+  }
   bool success = CanEmbed(transport_node_id);
   if (success) {
     // Only allow a node to be the root for one connection.
     const NodeId node_id(NodeIdFromTransportId(transport_node_id));
     ViewManagerServiceImpl* connection_by_url =
         root_node_manager_->GetConnectionByCreator(id_, url.To<std::string>());
     ViewManagerServiceImpl* connection_with_node_as_root =
         root_node_manager_->GetConnectionWithRoot(node_id);
     if ((connection_by_url != connection_with_node_as_root ||
          (!connection_by_url && !connection_with_node_as_root)) &&
@@ skipping 45 matching lines @@
 
   client()->OnViewManagerConnectionEstablished(
       id_,
       creator_url_,
       NodesToNodeDatas(to_send));
 }
 
 }  // namespace service
 }  // namespace view_manager
 }  // namespace mojo