Take GL version and extensions correctly into account when binding functions

ui/gl/gl_surface_win.cc

 // 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.
 
 #include "ui/gl/gl_surface.h"
 
 #include <dwmapi.h>
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ skipping 65 matching lines @@
           timing_info.rateRefresh.uiNumerator);
       callback.Run(timebase, interval);
     }
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DWMVSyncProvider);
 };
 
 // Helper routine that does one-off initialization like determining the
-// pixel format and initializing the GL bindings.
+// pixel format.
 bool GLSurface::InitializeOneOffInternal() {
   switch (GetGLImplementation()) {
     case kGLImplementationDesktopGL:
       if (!GLSurfaceWGL::InitializeOneOff()) {
         LOG(ERROR) << "GLSurfaceWGL::InitializeOneOff failed.";
         return false;
       }
       break;
     case kGLImplementationEGLGLES2:
       if (!GLSurfaceEGL::InitializeOneOff()) {
@@ skipping 185 matching lines @@
     }
     case kGLImplementationMockGL:
       return new GLSurfaceStub;
     default:
       NOTREACHED();
       return NULL;
   }
 }
 
 }  // namespace gfx