gpu: Add CHROMIUM_copy_image extension.

ui/gl/gl_image_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 <memory>
 
@@ skipping 176 matching lines @@
 bool GLImageGLX::CopyTexImage(unsigned target) {
   return false;
 }
 
 bool GLImageGLX::CopyTexSubImage(unsigned target,
                                  const gfx::Point& offset,
                                  const gfx::Rect& rect) {
   return false;
 }
 
+bool GLImageGLX::CopySubImageData(unsigned texture_id,
+                                  const gfx::Point& offset,
+                                  const gfx::Rect& rect,
+                                  GLFence* in_fence,
+                                  GLFence* out_fence) {
+  return false;
+}
+
 bool GLImageGLX::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                                       int z_order,
                                       gfx::OverlayTransform transform,
                                       const gfx::Rect& bounds_rect,
                                       const gfx::RectF& crop_rect) {
   return false;
 }
 
 void GLImageGLX::OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd,
                               uint64_t process_tracing_id,
                               const std::string& dump_name) {
   // TODO(ericrk): Implement GLImage OnMemoryDump. crbug.com/514914
 }
 
 }  // namespace gl