Add missing IWYU message_loop.h includes.

chrome/browser/net/sdch_browsertest.cc

 // Copyright 2014 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.
 
 // End-to-end SDCH tests.  Uses the embedded test server to return SDCH
 // results
 
 #include <stddef.h>
 #include <stdint.h>
 #include <utility>
 
 #include "base/base64.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browsing_data/browsing_data_helper.h"
 #include "chrome/browser/browsing_data/chrome_browsing_data_remover_delegate.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 723 matching lines @@
   ASSERT_TRUE(SetupIncognitoBrowser());
   ASSERT_TRUE(ForceSdchDictionaryLoad(incognito_browser()));
 
   // Data fetches on main browser should not be SDCH encoded.
   bool sdch_encoding_used = true;
   ASSERT_TRUE(GetData(&sdch_encoding_used));
   EXPECT_FALSE(sdch_encoding_used);
 }
 
 }  // namespace