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

ppapi/proxy/proxy_completion_callback_factory.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 PPAPI_PROXY_PROXY_COMPLETION_CALLBACK_FACTORY_H_
 #define PPAPI_PROXY_PROXY_COMPLETION_CALLBACK_FACTORY_H_
 
 #include "base/logging.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "ppapi/cpp/completion_callback.h"
 #include "ppapi/utility/completion_callback_factory.h"
 
 namespace ppapi {
 namespace proxy {
 
 // This class is just like pp::NonThreadSafeThreadTraits but rather than using
 // pp::Module::core (which doesn't exist), it uses Chrome threads which do.
 class ProxyNonThreadSafeThreadTraits {
  public:
@@ skipping 58 matching lines @@
   ProxyCompletionCallbackFactory()
       : pp::CompletionCallbackFactory<T, ProxyNonThreadSafeThreadTraits>() {}
   ProxyCompletionCallbackFactory(T* t)
       : pp::CompletionCallbackFactory<T, ProxyNonThreadSafeThreadTraits>(t) {}
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PROXY_COMPLETION_CALLBACK_FACTORY_H_