Remove reference counting from media::VideoDecoder and friends.

media/filters/gpu_video_decoder.h

Index: media/filters/gpu_video_decoder.h
diff --git a/media/filters/gpu_video_decoder.h b/media/filters/gpu_video_decoder.h
index 61c8b562a061a17d8ecf8cbfce48ff57cb5e0b9f..63c3e8d90d3accc11205b5b471143fcf11df9f12 100644
--- a/media/filters/gpu_video_decoder.h
+++ b/media/filters/gpu_video_decoder.h
@@ -10,6 +10,7 @@
 #include <utility>
 #include <vector>
 
+#include "base/memory/weak_ptr.h"
 #include "media/base/pipeline_status.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/video_decoder.h"
@@ -163,6 +164,8 @@ class MEDIA_EXPORT GpuVideoDecoder
   // MessageLoop on which to fire callbacks and trampoline calls to this class
   // if they arrive on other loops.
   scoped_refptr<base::MessageLoopProxy> gvd_loop_proxy_;
+  base::WeakPtrFactory<GpuVideoDecoder> weak_factory_;
+  base::WeakPtr<GpuVideoDecoder> weak_this_;
 
   // Message loop on which to makes all calls to vda_.  (beware this loop may be
   // paused during the Pause/Flush/Stop dance PipelineImpl::Stop() goes