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

sync/notifier/ack_tracker_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/notifier/ack_tracker.h"
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "base/time/tick_clock.h"
 #include "google/cacheinvalidation/include/types.h"
 #include "google/cacheinvalidation/types.pb.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace syncer {
 
 namespace {
 
@@ skipping 323 matching lines @@
   EXPECT_EQ(base::TimeDelta::FromSeconds(120), GetTimerDelay());
   fake_tick_clock_.LeapForward(120);
   EXPECT_CALL(delegate_, OnTimeout(ids));
   EXPECT_TRUE(TriggerTimeoutNow());
 
   ack_tracker_.Ack(ids);
   EXPECT_TRUE(ack_tracker_.IsQueueEmptyForTest());
 }
 
 }  // namespace syncer