gpu: Add the ability to wait on upload completion.

ui/gl/async_pixel_transfer_delegate_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/async_pixel_transfer_delegate_stub.h"
 
 #include "base/shared_memory.h"
 #include "build/build_config.h"
 #include "ui/gl/gl_bindings.h"
 
@@ skipping 121 matching lines @@
       tex_params.yoffset,
       tex_params.width,
       tex_params.height,
       tex_params.format,
       tex_params.type,
       data);
   texture_upload_count_++;
   total_texture_upload_time_ += base::TimeTicks::HighResNow() - begin_time;
 }
 
+void AsyncPixelTransferDelegateStub::WaitForTransferCompletion(
+    AsyncPixelTransferState* state) {
+  // Already done.
+}
+
 uint32 AsyncPixelTransferDelegateStub::GetTextureUploadCount() {
   return texture_upload_count_;
 }
 
 base::TimeDelta AsyncPixelTransferDelegateStub::GetTotalTextureUploadTime() {
   return total_texture_upload_time_;
 }
 
 }  // namespace gfx