Use a direct include of the message_loop header in ui/, part 1.

ui/aura/root_window.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_ROOT_WINDOW_H_
 #define UI_AURA_ROOT_WINDOW_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "ui/aura/aura_export.h"
 #include "ui/aura/client/capture_delegate.h"
 #include "ui/aura/root_window_host_delegate.h"
 #include "ui/aura/window.h"
 #include "ui/base/cursor/cursor.h"
 #include "ui/base/events/event_constants.h"
 #include "ui/base/events/event_dispatcher.h"
 #include "ui/base/gestures/gesture_recognizer.h"
 #include "ui/base/gestures/gesture_types.h"
 #include "ui/compositor/compositor.h"
@@ skipping 429 matching lines @@
   scoped_ptr<ui::ViewProp> prop_;
 
   scoped_ptr<RootWindowTransformer> transformer_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindow);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_ROOT_WINDOW_H_