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

sync/internal_api/js_mutation_event_observer_unittest.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 "sync/internal_api/js_mutation_event_observer.h"
 
 #include "base/basictypes.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "base/values.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/util/weak_handle.h"
 #include "sync/js/js_event_details.h"
 #include "sync/js/js_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace syncer {
 namespace {
 
@@ skipping 90 matching lines @@
 
   for (int i = FIRST_REAL_MODEL_TYPE; i < MODEL_TYPE_COUNT; ++i) {
     js_mutation_event_observer_.OnChangesComplete(
         ModelTypeFromInt(i));
   }
   PumpLoop();
 }
 
 }  // namespace
 }  // namespace syncer