Use MGLGetProcAddress to access OpenGL functions

examples/spinning_cube/spinning_cube.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 EXAMPLES_SPINNING_CUBE_SPINNING_CUBE_H_
 #define EXAMPLES_SPINNING_CUBE_SPINNING_CUBE_H_
 
 #include <stdint.h>
 
 #include "base/memory/scoped_ptr.h"
 
 namespace examples {
 
 class SpinningCube {
  public:
+  class GLInterface;
+
   SpinningCube();
   ~SpinningCube();
 
   void Init();
   void set_direction(int direction) { direction_ = direction; }
   void set_color(float r, float g, float b) {
     color_[0] = r;
     color_[1] = g;
     color_[2] = b;
   }
   void set_size(uint32_t width, uint32_t height) {
     width_ = width;
     height_ = height;
   }
   void SetFlingMultiplier(float drag_distance, float drag_time);
   void UpdateForTimeDelta(float delta_time);
   void UpdateForDragDistance(float distance);
   void Draw();
 
   void OnGLContextLost();
 
  private:
   class GLState;
 
   void Update();
 
   bool initialized_;
   uint32_t width_;
   uint32_t height_;
+  scoped_ptr<GLInterface> gl_;
   scoped_ptr<GLState> state_;
   float fling_multiplier_;
   int direction_;
   float color_[3];
 };
 
 }  // namespace examples
 
 #endif  // EXAMPLES_SPINNING_CUBE_SPINNING_CUBE_H_