GPU: Keep track of the last real context and real surface made current.

ui/gl/gl_context_cgl.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.
 
 #ifndef UI_GL_GL_CONTEXT_CGL_H_
 #define UI_GL_GL_CONTEXT_CGL_H_
 
 #include <OpenGL/CGLTypes.h>
 
 #include "ui/gl/gl_context.h"
 
 namespace gfx {
 
 class GLSurface;
 
 // Encapsulates a CGL OpenGL context.
-class GLContextCGL : public GLContext {
+class GLContextCGL : public GLContextReal {
  public:
   explicit GLContextCGL(GLShareGroup* share_group);
 
   // Implement GLContext.
   virtual bool Initialize(GLSurface* compatible_surface,
                           GpuPreference gpu_preference) OVERRIDE;
   virtual void Destroy() OVERRIDE;
   virtual bool MakeCurrent(GLSurface* surface) OVERRIDE;
   virtual void ReleaseCurrent(GLSurface* surface) OVERRIDE;
   virtual bool IsCurrent(GLSurface* surface) OVERRIDE;
@@ skipping 16 matching lines @@
   int screen_;
   int renderer_id_;
   bool safe_to_force_gpu_switch_;
 
   DISALLOW_COPY_AND_ASSIGN(GLContextCGL);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_CONTEXT_CGL_H_