Fix the frame freezing issue observed during a config change in the H.264 decoder on Windows

media/gpu/dxva_video_decode_accelerator_win.h

Index: media/gpu/dxva_video_decode_accelerator_win.h
diff --git a/media/gpu/dxva_video_decode_accelerator_win.h b/media/gpu/dxva_video_decode_accelerator_win.h
index 4bbfc856c26c0f7508d40911fa998cf53941f1f2..0f34aeaf83cc27e0c30174bf84720e881131b8b8 100644
--- a/media/gpu/dxva_video_decode_accelerator_win.h
+++ b/media/gpu/dxva_video_decode_accelerator_win.h
@@ -489,6 +489,9 @@ class MEDIA_GPU_EXPORT DXVAVideoDecodeAccelerator
   // Contains the initialization parameters for the video.
   Config config_;
 
+  // Set to true if we are processing a video configuration change.
+  bool processing_config_changed_;
+
   // WeakPtrFactory for posting tasks back to |this|.
   base::WeakPtrFactory<DXVAVideoDecodeAccelerator> weak_this_factory_;