Support dynamic switching between integrated and discrete GPUs on Mac OS X.

ui/gfx/gl/gl_context_wgl.cc

 // Copyright (c) 2011 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.
 
 // This file implements the GLContextWGL and PbufferGLContext classes.
 
 #include "ui/gfx/gl/gl_context_wgl.h"
 
 #include "base/logging.h"
 #include "ui/gfx/gl/gl_bindings.h"
@@ skipping 19 matching lines @@
     const char* extensions = wglGetExtensionsStringARB(
         GLSurfaceWGL::GetDisplay());
     if (extensions) {
       return GLContext::GetExtensions() + " " + extensions;
     }
   }
 
   return GLContext::GetExtensions();
 }
 
-bool GLContextWGL::Initialize(GLSurface* compatible_surface) {
+bool GLContextWGL::Initialize(
+    GLSurface* compatible_surface, GpuPreference gpu_preference) {
   GLSurfaceWGL* surface_wgl = static_cast<GLSurfaceWGL*>(compatible_surface);
 
   // TODO(apatrick): When contexts and surfaces are separated, we won't be
   // able to use surface_ here. Either use a display device context or a
   // surface that the context is compatible with not necessarily limited to
   // rendering to.
   context_ = wglCreateContext(static_cast<HDC>(surface_wgl->GetHandle()));
   if (!context_) {
     LOG(ERROR) << "Failed to create GL context.";
     Destroy();
@@ skipping 73 matching lines @@
   if (HasExtension("WGL_EXT_swap_control") && wglSwapIntervalEXT) {
     wglSwapIntervalEXT(interval);
   } else {
       LOG(WARNING) <<
           "Could not disable vsync: driver does not "
           "support WGL_EXT_swap_control";
   }
 }
 
 }  // namespace gfx