Add support for EXT_image_flush_external extension

media/gpu/avda_codec_image.h

Index: media/gpu/avda_codec_image.h
diff --git a/media/gpu/avda_codec_image.h b/media/gpu/avda_codec_image.h
index a60e7d7050da091954cf2594ea6bdc3da812280f..72f706831ac10492a7f6977edb8a5e5fdcc9263a 100644
--- a/media/gpu/avda_codec_image.h
+++ b/media/gpu/avda_codec_image.h
@@ -46,6 +46,7 @@ class AVDACodecImage : public gpu::gles2::GLStreamTextureImage {
                             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;