Rename RootWindowHost* to WindowTreeHost*

ui/aura/env.h

 // Copyright (c) 2012 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 UI_AURA_ENV_H_
 #define UI_AURA_ENV_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/observer_list.h"
@@ skipping 61 matching lines @@
     !defined(USE_GTK_MESSAGE_PUMP)
   base::MessageLoop::Dispatcher* GetDispatcher();
 #endif
 
   // Invoked by RootWindow when its host is activated.
   void RootWindowActivated(RootWindow* root_window);
 
  private:
   friend class test::EnvTestHelper;
   friend class Window;
-  friend class RootWindowHost;
+  friend class WindowTreeHost;
 
   void Init();
 
   // Called by the Window when it is initialized. Notifies observers.
   void NotifyWindowInitialized(Window* window);
 
   // Called by the RootWindow when it is initialized. Notifies observers.
   void NotifyRootWindowInitialized(RootWindow* root_window);
 
   // Overridden from ui::EventTarget:
@@ skipping 18 matching lines @@
 #endif
 
   scoped_ptr<InputStateLookup> input_state_lookup_;
 
   DISALLOW_COPY_AND_ASSIGN(Env);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_ENV_H_