gpu: Add CopyTexImage function to GLImage API.

ui/gl/gl_image_io_surface.cc

 // Copyright 2013 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_io_surface.h"
 
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
 
 // Note that this must be included after gl_bindings.h to avoid conflicts.
@@ skipping 46 matching lines @@
                                               io_surface_.get(),
                                               0);
   if (cgl_error != kCGLNoError) {
     LOG(ERROR) << "Error in CGLTexImageIOSurface2D";
     return false;
   }
 
   return true;
 }
 
+bool GLImageIOSurface::CopyTexImage(unsigned target) {
+  return false;
+}
+
 bool GLImageIOSurface::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                                             int z_order,
                                             OverlayTransform transform,
                                             const Rect& bounds_rect,
                                             const RectF& crop_rect) {
   return false;
 }
 
 }  // namespace gfx