Add lock support for in process context provider.

webkit/common/gpu/context_provider_in_process.h

 // Copyright (c) 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 WEBKIT_COMMON_GPU_CONTEXT_PROVIDER_IN_PROCESS_H_
 #define WEBKIT_COMMON_GPU_CONTEXT_PROVIDER_IN_PROCESS_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 61 matching lines @@
 
   scoped_ptr<gpu_blink::WebGraphicsContext3DInProcessCommandBufferImpl>
       context3d_;
   scoped_ptr<GrContextForWebGraphicsContext3D> gr_context_;
 
   LostContextCallback lost_context_callback_;
 
   base::Lock destroyed_lock_;
   bool destroyed_;
 
+  base::Lock context_lock_;
   std::string debug_name_;
   class LostContextCallbackProxy;
   scoped_ptr<LostContextCallbackProxy> lost_context_callback_proxy_;
 
   cc::ContextProvider::Capabilities capabilities_;
 
   DISALLOW_COPY_AND_ASSIGN(ContextProviderInProcess);
 };
 
 }  // namespace gpu
 }  // namespace webkit
 
 #endif  // WEBKIT_COMMON_GPU_CONTEXT_PROVIDER_IN_PROCESS_H_