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

ppapi/proxy/printing_resource_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 <cstring>
 
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "ppapi/c/dev/ppb_printing_dev.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/proxy/locking_resource_releaser.h"
-#include "ppapi/proxy/printing_resource.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/proxy/ppapi_proxy_test.h"
+#include "ppapi/proxy/printing_resource.h"
 #include "ppapi/thunk/thunk.h"
 
 namespace ppapi {
 namespace proxy {
 
 namespace {
 
 typedef PluginProxyTest PrintingResourceTest;
 
 bool g_callback_called;
@@ skipping 69 matching lines @@
             output_settings.print_scaling_option);
   EXPECT_EQ(reply_settings.grayscale, output_settings.grayscale);
   EXPECT_EQ(reply_settings.format, output_settings.format);
 
   EXPECT_EQ(g_callback_result, PP_OK);
   EXPECT_EQ(g_callback_called, true);
 }
 
 }  // namespace proxy
 }  // namespace ppapi