Add EmbedRoot to ViewManagerService.

mojo/services/view_manager/view_manager_service_impl.cc

Index: mojo/services/view_manager/view_manager_service_impl.cc
diff --git a/mojo/services/view_manager/view_manager_service_impl.cc b/mojo/services/view_manager/view_manager_service_impl.cc
index ee2c795001ded8b944f3c016b77010483627373c..c115d54d883ba5550bfdcaaef0ac6c7beb637a9f 100644
--- a/mojo/services/view_manager/view_manager_service_impl.cc
+++ b/mojo/services/view_manager/view_manager_service_impl.cc
@@ -753,6 +753,12 @@ void ViewManagerServiceImpl::Embed(const String& url,
   callback.Run(success);
 }
 
+void ViewManagerServiceImpl::EmbedRoot(const String& url,
+                                       const Callback<void(bool)>& callback) {
+  root_node_manager_->EmbedRoot(url);
+  callback.Run(true);
+}
+
 void ViewManagerServiceImpl::DispatchOnViewInputEvent(Id transport_view_id,
                                                       EventPtr event) {
   // We only allow the WM to dispatch events. At some point this function will