gpu: Add CopyTexImage function to GLImage API.

ui/gl/gl_image_surface_texture.cc

 // Copyright 2014 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_surface_texture.h"
 
 #include "base/debug/trace_event.h"
 #include "ui/gl/android/surface_texture.h"
 #include "ui/gl/android/surface_texture_tracker.h"
 
@@ skipping 59 matching lines @@
     // This will attach the surface texture to the texture currently bound to
     // GL_TEXTURE_EXTERNAL_OES target.
     surface_texture_->AttachToGLContext();
     texture_id_ = texture_id;
   }
 
   surface_texture_->UpdateTexImage();
   return true;
 }
 
+bool GLImageSurfaceTexture::CopyTexImage(unsigned target) {
+  return false;
+}
+
 bool GLImageSurfaceTexture::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                                                  int z_order,
                                                  OverlayTransform transform,
                                                  const Rect& bounds_rect,
                                                  const RectF& crop_rect) {
   return false;
 }
 
 }  // namespace gfx