Add support for EXT_image_flush_external extension

gpu/ipc/service/stream_texture_android.h

 // Copyright (c) 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.
 
 #ifndef GPU_IPC_SERVICE_STREAM_TEXTURE_ANDROID_H_
 #define GPU_IPC_SERVICE_STREAM_TEXTURE_ANDROID_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 38 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;
 
   // gpu::gles2::GLStreamTextureMatrix implementation
   void GetTextureMatrix(float xform[16]) override;
 
   // GpuCommandBufferStub::DestructionObserver implementation.
   void OnWillDestroyStub() override;
 
@@ skipping 35 matching lines @@
   unsigned vertex_buffer_;
   int u_xform_location_;
 
   base::WeakPtrFactory<StreamTexture> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(StreamTexture);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_IPC_SERVICE_STREAM_TEXTURE_ANDROID_H_