Fix build error in release mode.

content/renderer/gpu/renderer_gl_context.h

 // Copyright (c) 2011 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.
 
 // This API is consistent with other OpenGL setup APIs like window's WGL
 // and pepper's PGL. This API is used to manage OpenGL RendererGLContexts in the
 // Chrome renderer process in a way that is consistent with other platforms.
 
 #ifndef CONTENT_RENDERER_GPU_RENDERER_GL_CONTEXT_H_
 #define CONTENT_RENDERER_GPU_RENDERER_GL_CONTEXT_H_
 #pragma once
 
 #include "base/callback_old.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/threading/non_thread_safe.h"
 #include "build/build_config.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/size.h"
 
 class GpuChannelHost;
-class MessageLoop;
 class CommandBufferProxy;
 class GURL;
 class Task;
 class TransportTextureHost;
 
 namespace gpu {
 namespace gles2 {
 class GLES2CmdHelper;
 class GLES2Implementation;
 }
 }
 
-class RendererGLContext : public base::SupportsWeakPtr<RendererGLContext> {
+class RendererGLContext : public base::SupportsWeakPtr<RendererGLContext>,
+                          public base::NonThreadSafe {
  public:
   // These are the same error codes as used by EGL.
   enum Error {
     SUCCESS               = 0x3000,
     NOT_INITIALIZED       = 0x3001,
     BAD_ATTRIBUTE         = 0x3004,
     BAD_RendererGLContext = 0x3006,
     CONTEXT_LOST          = 0x300E
   };
 
@@ skipping 146 matching lines @@
   scoped_refptr<GpuChannelHost> channel_;
   base::WeakPtr<RendererGLContext> parent_;
   scoped_ptr<Callback1<ContextLostReason>::Type> context_lost_callback_;
   uint32 parent_texture_id_;
   CommandBufferProxy* command_buffer_;
   gpu::gles2::GLES2CmdHelper* gles2_helper_;
   int32 transfer_buffer_id_;
   gpu::gles2::GLES2Implementation* gles2_implementation_;
   Error last_error_;
   int frame_number_;
-#ifndef NDEBUG
-  // Used to assert that this object is used on a single thread.
-  MessageLoop* message_loop_;
-#endif
 
   DISALLOW_COPY_AND_ASSIGN(RendererGLContext);
 };
 
 #endif  // CONTENT_RENDERER_GPU_RENDERER_GL_CONTEXT_H_