Add support for EXT_image_flush_external extension

gpu/command_buffer/service/texture_definition.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 "gpu/command_buffer/service/texture_definition.h"
 
 #include <stdint.h>
 
 #include <list>
 
@@ skipping 32 matching lines @@
   void ReleaseTexImage(unsigned target) override;
   bool CopyTexImage(unsigned target) override;
   bool CopyTexSubImage(unsigned target,
                        const gfx::Point& offset,
                        const gfx::Rect& rect) override;
   bool ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                             int z_order,
                             gfx::OverlayTransform transform,
                             const gfx::Rect& bounds_rect,
                             const gfx::RectF& crop_rect) override;
+  void Flush() override {}
   void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd,
                     uint64_t process_tracing_id,
                     const std::string& dump_name) override;
 
  protected:
   ~GLImageSync() override;
 
  private:
   scoped_refptr<NativeImageBuffer> buffer_;
   gfx::Size size_;
@@ skipping 402 matching lines @@
   return true;
 }
 
 bool TextureDefinition::SafeToRenderFrom() const {
   return level_info_.cleared_rect.Contains(
       gfx::Rect(level_info_.width, level_info_.height));
 }
 
 }  // namespace gles2
 }  // namespace gpu