Fix build with gcc 4.8 and C++11 support enabled

chrome/browser/sync/glue/sync_backend_host_impl.h

 // Copyright 2013 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.
 
 #ifndef CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_IMPL_H_
 #define CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_IMPL_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 76 matching lines @@
       syncer::ReportUnrecoverableErrorFunction
           report_unrecoverable_error_function,
       syncer::NetworkResources* network_resources) OVERRIDE;
   virtual void UpdateCredentials(
       const syncer::SyncCredentials& credentials) OVERRIDE;
   virtual void StartSyncingWithServer() OVERRIDE;
   virtual void SetEncryptionPassphrase(
       const std::string& passphrase,
       bool is_explicit) OVERRIDE;
   virtual bool SetDecryptionPassphrase(const std::string& passphrase)
-      WARN_UNUSED_RESULT OVERRIDE;
+      OVERRIDE WARN_UNUSED_RESULT;
   virtual void StopSyncingForShutdown() OVERRIDE;
   virtual scoped_ptr<base::Thread> Shutdown(ShutdownOption option) OVERRIDE;
   virtual void UnregisterInvalidationIds() OVERRIDE;
   virtual void ConfigureDataTypes(
       syncer::ConfigureReason reason,
       const DataTypeConfigStateMap& config_state_map,
       const base::Callback<void(syncer::ModelTypeSet,
                                 syncer::ModelTypeSet)>& ready_task,
       const base::Callback<void()>& retry_callback) OVERRIDE;
   virtual void EnableEncryptEverything() OVERRIDE;
@@ skipping 205 matching lines @@
 
   base::WeakPtrFactory<SyncBackendHostImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHostImpl);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_IMPL_H_