Remove #pragma once from sync

sync/test/engine/mock_connection_manager.h

 // 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.
 //
 // Mock ServerConnectionManager class for use in client unit tests.
 
 #ifndef SYNC_TEST_ENGINE_MOCK_CONNECTION_MANAGER_H_
 #define SYNC_TEST_ENGINE_MOCK_CONNECTION_MANAGER_H_
-#pragma once
 
 #include <bitset>
 #include <list>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_vector.h"
 #include "sync/engine/net/server_connection_manager.h"
@@ skipping 326 matching lines @@
   std::string next_token_;
 
   sync_pb::ClientToServerMessage last_request_;
 
   DISALLOW_COPY_AND_ASSIGN(MockConnectionManager);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_TEST_ENGINE_MOCK_CONNECTION_MANAGER_H_