Remove using the Shell desktop Window when we don't have an acceleated widget.

ui/aura/remote_root_window_host_win.h

Index: ui/aura/remote_root_window_host_win.h
===================================================================
--- ui/aura/remote_root_window_host_win.h	(revision 217576)
+++ ui/aura/remote_root_window_host_win.h	(working copy)
@@ -86,12 +86,15 @@
 // frontend process, which forwards input events to this class.
 class AURA_EXPORT RemoteRootWindowHostWin : public RootWindowHost {
  public:
+  // Returns the only RemoteRootWindowHostWin, if this is the first time
+  // this function is called, it will call Create() wiht empty bounds.
   static RemoteRootWindowHostWin* Instance();
   static RemoteRootWindowHostWin* Create(const gfx::Rect& bounds);
 
   // Called when the remote process has established its IPC connection.
-  // The |host| can be used when we need to send a message to it.
-  void Connected(IPC::Sender* host);
+  // The |host| can be used when we need to send a message to it and
+  // |remote_window| is the actual window owned by the viewer process.
+  void Connected(IPC::Sender* host, HWND remote_window);
   // Called when the remote process has closed its IPC connection.
   void Disconnected();
 
@@ -203,6 +206,7 @@
                                uint32 flags,
                                bool is_character);
 
+  HWND remote_window_;
   RootWindowHostDelegate* delegate_;
   IPC::Sender* host_;
   scoped_ptr<ui::ViewProp> prop_;