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

ui/aura/root_window_host_win.cc

 // 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.
 
 #include "ui/aura/root_window_host_win.h"
 
 #include <windows.h>
 
 #include <algorithm>
 
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/root_window.h"
 #include "ui/base/cursor/cursor_loader_win.h"
 #include "ui/base/events/event.h"
 #include "ui/base/view_prop.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/insets.h"
 #include "ui/gfx/screen.h"
 
@@ skipping 294 matching lines @@
 namespace test {
 
 // static
 void SetUsePopupAsRootWindowForTest(bool use) {
   use_popup_as_root_window_for_test = use;
 }
 
 }  // namespace test
 
 }  // namespace aura