ui: Cleanup class/struct forward declarations

ui/aura/mus/window_tree_host_mus.h

 // Copyright 2015 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_MUS_WINDOW_TREE_HOST_MUS_H_
 #define UI_AURA_MUS_WINDOW_TREE_HOST_MUS_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "services/service_manager/public/cpp/connector.h"
 #include "ui/aura/aura_export.h"
 #include "ui/aura/window_tree_host_platform.h"
 
-class SkBitmap;
-
 namespace display {
 class Display;
 }
 
-namespace service_manager {
-class Connector;
-}
-
 namespace aura {
 
 class InputMethodMus;
 class WindowPortMus;
 class WindowTreeClient;
 class WindowTreeHostMusDelegate;
 
 class AURA_EXPORT WindowTreeHostMus : public aura::WindowTreeHostPlatform {
  public:
   WindowTreeHostMus(std::unique_ptr<WindowPortMus> window_port,
@@ skipping 34 matching lines @@
   bool in_set_bounds_from_server_ = false;
 
   std::unique_ptr<InputMethodMus> input_method_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHostMus);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_MUS_WINDOW_TREE_HOST_MUS_H_