Allow EmbedRoot to be called multiple times.

mojo/services/public/cpp/view_manager/view_manager.h

Index: mojo/services/public/cpp/view_manager/view_manager.h
diff --git a/mojo/services/public/cpp/view_manager/view_manager.h b/mojo/services/public/cpp/view_manager/view_manager.h
index 3c55e30732dbda2a33d8ea15ef4415486fb2f68a..83b1199fa0dbda4ba8bbf5659ac523db3efb7f49 100644
--- a/mojo/services/public/cpp/view_manager/view_manager.h
+++ b/mojo/services/public/cpp/view_manager/view_manager.h
@@ -17,8 +17,8 @@ namespace view_manager {
 
 class Node;
 class View;
-class ViewEventDispatcher;
 class ViewManagerDelegate;
+class WindowManagerDelegate;
 
 class ViewManager {
  public:
@@ -26,12 +26,13 @@ class ViewManager {
   static void ConfigureIncomingConnection(ApplicationConnection* connection,
                                           ViewManagerDelegate* delegate);
 
-  // Sets the event dispatcher. Can only be called by the app rendering to the
-  // root Node of the hierarchy.
-  virtual void SetEventDispatcher(ViewEventDispatcher* dispatcher) = 0;
+  // Sets the window manager delegate. Can only be called by the app embedded at
+  // the service root node.
+  virtual void SetWindowManagerDelegate(
+      WindowManagerDelegate* window_manager_delegate) = 0;
 
   // Dispatches the supplied event to the specified View. Can be called only
-  // by the application that called SetEventDispatcher().
+  // by the application that called SetWindowManagerDelegate().
   virtual void DispatchEvent(View* target, EventPtr event) = 0;
 
   // Returns the URL of the application that embedded this application.