Make GL calls go through subclassable class.

ui/gl/gl_surface_glx.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.
 
 extern "C" {
 #include <X11/Xlib.h>
 }
 
 #include "ui/gl/gl_surface_glx.h"
 
@@ skipping 104 matching lines @@
   return true;
 }
 
 void NativeViewGLSurfaceGLX::Destroy() {
 }
 
 bool NativeViewGLSurfaceGLX::Resize(const gfx::Size& size) {
   // On Intel drivers, the frame buffer won't be resize until the next swap. If
   // we only do PostSubBuffer, then we're stuck in the old size. Force a swap
   // now.
-  if (gfx::g_GLX_MESA_copy_sub_buffer && size_ != size)
+  if (gfx::g_driver_glx.ext.b_GLX_MESA_copy_sub_buffer && size_ != size)
     SwapBuffers();
   size_ = size;
   return true;
 }
 
 bool NativeViewGLSurfaceGLX::IsOffscreen() {
   return false;
 }
 
 bool NativeViewGLSurfaceGLX::SwapBuffers() {
   glXSwapBuffers(g_display, window_);
   // For latency_tests.cc:
   UNSHIPPED_TRACE_EVENT_INSTANT0("test_gpu", "CompositorSwapBuffersComplete");
   return true;
 }
 
 gfx::Size NativeViewGLSurfaceGLX::GetSize() {
   return size_;
 }
 
 void* NativeViewGLSurfaceGLX::GetHandle() {
   return reinterpret_cast<void*>(window_);
 }
 
 std::string NativeViewGLSurfaceGLX::GetExtensions() {
   std::string extensions = GLSurface::GetExtensions();
-  if (g_GLX_MESA_copy_sub_buffer) {
+  if (gfx::g_driver_glx.ext.b_GLX_MESA_copy_sub_buffer) {
     extensions += extensions.empty() ? "" : " ";
     extensions += "GL_CHROMIUM_post_sub_buffer";
   }
   return extensions;
 }
 
 void* NativeViewGLSurfaceGLX::GetConfig() {
   if (!config_) {
     // This code path is expensive, but we only take it when
     // attempting to use GLX_ARB_create_context_robustness, in which
@@ skipping 49 matching lines @@
     if (found) {
       config_ = configs.get()[i];
     }
   }
 
   return config_;
 }
 
 bool NativeViewGLSurfaceGLX::PostSubBuffer(
     int x, int y, int width, int height) {
-  DCHECK(g_GLX_MESA_copy_sub_buffer);
+  DCHECK(gfx::g_driver_glx.ext.b_GLX_MESA_copy_sub_buffer);
   glXCopySubBufferMESA(g_display, window_, x, y, width, height);
   return true;
 }
 
 NativeViewGLSurfaceGLX::NativeViewGLSurfaceGLX()
   : window_(0),
     config_(NULL) {
 }
 
 NativeViewGLSurfaceGLX::~NativeViewGLSurfaceGLX() {
@@ skipping 83 matching lines @@
 
 void* PbufferGLSurfaceGLX::GetConfig() {
   return config_;
 }
 
 PbufferGLSurfaceGLX::~PbufferGLSurfaceGLX() {
   Destroy();
 }
 
 }  // namespace gfx