Add an additional VDA::Flush() mode to return all allocated buffers.

content/common/gpu/media/fake_video_decode_accelerator.h

Index: content/common/gpu/media/fake_video_decode_accelerator.h
diff --git a/content/common/gpu/media/fake_video_decode_accelerator.h b/content/common/gpu/media/fake_video_decode_accelerator.h
index 10d47822b45faac4a0d1bcc3c5041138751903cc..6a33a8f2091d0075f7404bd30ff2cf03b5d4517f 100644
--- a/content/common/gpu/media/fake_video_decode_accelerator.h
+++ b/content/common/gpu/media/fake_video_decode_accelerator.h
@@ -43,6 +43,7 @@ class CONTENT_EXPORT FakeVideoDecodeAccelerator
 
  private:
   void DoPictureReady();
+  void ReturnPicture(int32_t picture_buffer_id, int32_t bitstream_buffer_id);
 
   // The message loop that created the class. Used for all callbacks. This
   // class expects all calls to this class to be on this message loop (not
@@ -54,6 +55,8 @@ class CONTENT_EXPORT FakeVideoDecodeAccelerator
   // Make our context current before running any GL entry points.
   MakeGLContextCurrentCallback make_context_current_cb_;
 
+  Config config_;
+
   // Output picture size.
   gfx::Size frame_buffer_size_;