Allow GLSurface to indicate that it supports a specific extension.

ui/gfx/gl/gl_surface.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.
 
 #include "ui/gfx/gl/gl_surface.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 72 matching lines @@
 bool GLSurface::Initialize()
 {
   return true;
 }
 
 bool GLSurface::Resize(const gfx::Size& size) {
   NOTIMPLEMENTED();
   return false;
 }
 
+std::string GLSurface::GetExtensions() {
+  DCHECK_EQ(GetCurrent(), this);
+  return std::string("");
+}
+
 unsigned int GLSurface::GetBackingFrameBufferObject() {
   return 0;
 }
 
-bool GLSurface::SupportsPostSubBuffer() {
-  return false;
-}
-
 bool GLSurface::PostSubBuffer(int x, int y, int width, int height) {
   return false;
 }
 
 bool GLSurface::OnMakeCurrent(GLContext* context) {
   return true;
 }
 
 void GLSurface::SetVisible(bool visible) {
 }
@@ skipping 78 matching lines @@
 
 void* GLSurfaceAdapter::GetConfig() {
   return surface_->GetConfig();
 }
 
 unsigned GLSurfaceAdapter::GetFormat() {
   return surface_->GetFormat();
 }
 
 }  // namespace gfx