Add missing #include around sequenced_worker_pool.h in //chrome

chrome/browser/gcm/gcm_profile_service_unittest.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.
 
 #include <memory>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "build/build_config.h"
 #include "chrome/browser/gcm/gcm_product_util.h"
 #include "chrome/browser/gcm/gcm_profile_service_factory.h"
 #include "chrome/browser/signin/profile_oauth2_token_service_factory.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/ui/webui/signin/login_ui_service_factory.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/test/base/testing_profile.h"
 #include "components/gcm_driver/gcm_profile_service.h"
 #if defined(OS_CHROMEOS)
@@ skipping 220 matching lines @@
   OutgoingMessage message;
   message.id = "1";
   message.data["key1"] = "value1";
   SendAndWaitForCompletion(message);
 
   EXPECT_EQ(message.id, send_message_id());
   EXPECT_EQ(GCMClient::SUCCESS, send_result());
 }
 
 }  // namespace gcm