gpu: Add CHROMIUM_copy_image extension.

ui/gl/gl_image_stub.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_image_stub.h"
 
 #include <GL/gl.h>
 
 namespace gl {
 
@@ skipping 14 matching lines @@
 bool GLImageStub::CopyTexImage(unsigned target) {
   return true;
 }
 
 bool GLImageStub::CopyTexSubImage(unsigned target,
                                   const gfx::Point& offset,
                                   const gfx::Rect& rect) {
   return true;
 }
 
+bool GLImageStub::CopySubImageData(unsigned texture_id,
+                                   const gfx::Point& offset,
+                                   const gfx::Rect& rect,
+                                   GLFence* in_fence,
+                                   GLFence* out_fence) {
+  return false;
+}
+
 bool GLImageStub::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                                        int z_order,
                                        gfx::OverlayTransform transform,
                                        const gfx::Rect& bounds_rect,
                                        const gfx::RectF& crop_rect) {
   return false;
 }
 
 }  // namespace gl