Use a direct include of the message_loop header in base/.

base/memory/weak_ptr_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 "base/memory/weak_ptr.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/debug/leak_annotations.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 namespace {
 
 template <class T>
 class OffThreadObjectCreator {
  public:
@@ skipping 559 matching lines @@
   background.Start();
   background.DeleteTarget(target.release());
 
   // Main thread attempts to dereference the target, violating thread binding.
   ASSERT_DEATH(arrow.target.get(), "");
 }
 
 #endif
 
 }  // namespace base