Make GL calls go through subclassable class.

ui/gl/gl_implementation_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 <vector>
 
 #include "base/at_exit.h"
 #include "base/base_paths.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/logging.h"
 #include "base/native_library.h"
 #include "base/path_service.h"
 #include "base/stringprintf.h"
 #include "base/threading/thread_restrictions.h"
 #include "ui/gl/gl_bindings.h"
+#include "ui/gl/gl_egl_api_implementation.h"
+#include "ui/gl/gl_gl_api_implementation.h"
 #include "ui/gl/gl_implementation.h"
+#include "ui/gl/gl_osmesa_api_implementation.h"
+#include "ui/gl/gl_wgl_api_implementation.h"
 
 #if defined(ENABLE_SWIFTSHADER)
 #include "software_renderer.h"
 #endif
 
 namespace gfx {
 
 namespace {
+
 // This is the D3DX_SDK_VERSION for the last 'separate' DirectX SDK which
 // is from June 2010. Since June 2012 Microsoft includes DirectX in the regular
 // Windows SDK and the D3DX library has been deprecated.
 const int kPinnedD3DXVersion = 43;
 
 void GL_BINDING_CALL MarshalClearDepthToClearDepthf(GLclampd depth) {
   glClearDepthf(static_cast<GLclampf>(depth));
 }
 
 void GL_BINDING_CALL MarshalDepthRangeToDepthRangef(GLclampd z_near,
@@ skipping 137 matching lines @@
       SetGLGetProcAddressProc(get_proc_address);
       AddGLNativeLibrary(egl_library);
       AddGLNativeLibrary(gles_library);
       SetGLImplementation(kGLImplementationEGLGLES2);
 
       InitializeGLBindingsGL();
       InitializeGLBindingsEGL();
 
       // These two functions take single precision float rather than double
       // precision float parameters in GLES.
-      ::gfx::g_glClearDepth = MarshalClearDepthToClearDepthf;
-      ::gfx::g_glDepthRange = MarshalDepthRangeToDepthRangef;
+      ::gfx::g_driver_gl.fn.glClearDepthFn = MarshalClearDepthToClearDepthf;
+      ::gfx::g_driver_gl.fn.glDepthRangeFn = MarshalDepthRangeToDepthRangef;
       break;
     }
     case kGLImplementationDesktopGL: {
       // When using Windows OpenGL, first try wglGetProcAddress and then
       // Windows GetProcAddress.
       base::NativeLibrary library = base::LoadNativeLibrary(
           FilePath(L"opengl32.dll"), NULL);
       if (!library) {
         DVLOG(1) << "opengl32.dll not found";
         return false;
@@ skipping 65 matching lines @@
 void ClearGLBindings() {
   ClearGLBindingsEGL();
   ClearGLBindingsGL();
   ClearGLBindingsOSMESA();
   ClearGLBindingsWGL();
   SetGLImplementation(kGLImplementationNone);
   UnloadGLNativeLibraries();
 }
 
 }  // namespace gfx