Use a direct include of the message_loop header in ppapi/, printing/, rlz/, sync/.

sync/test/engine/syncer_command_test.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 SYNC_TEST_ENGINE_SYNCER_COMMAND_TEST_H_
 #define SYNC_TEST_ENGINE_SYNCER_COMMAND_TEST_H_
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "sync/engine/model_changing_syncer_command.h"
 #include "sync/engine/traffic_recorder.h"
 #include "sync/internal_api/public/engine/model_safe_worker.h"
 #include "sync/sessions/debug_info_getter.h"
 #include "sync/sessions/sync_session.h"
 #include "sync/sessions/sync_session_context.h"
 #include "sync/syncable/directory.h"
 #include "sync/test/engine/fake_model_worker.h"
 #include "sync/test/engine/mock_connection_manager.h"
 #include "sync/test/engine/test_directory_setter_upper.h"
@@ skipping 195 matching lines @@
   virtual void TearDown() OVERRIDE;
   virtual syncable::Directory* directory() OVERRIDE;
 
  private:
   TestDirectorySetterUpper dir_maker_;
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_TEST_ENGINE_SYNCER_COMMAND_TEST_H_