MediaVideoStreamTrack should store weak reference to the media source.

content/renderer/media/media_stream_video_track.h

Index: content/renderer/media/media_stream_video_track.h
diff --git a/content/renderer/media/media_stream_video_track.h b/content/renderer/media/media_stream_video_track.h
index 9547c3d829cb8b4c49620548fe20110fee4054f4..e74e3bc29248dc43a086d1c3a852daf0d621eb0a 100644
--- a/content/renderer/media/media_stream_video_track.h
+++ b/content/renderer/media/media_stream_video_track.h
@@ -86,10 +86,8 @@ class CONTENT_EXPORT MediaStreamVideoTrack : public MediaStreamTrack {
 
   const blink::WebMediaConstraints constraints_;
 
-  // Weak ref to the source this tracks is connected to.  |source_| is owned
-  // by the blink::WebMediaStreamSource and is guaranteed to outlive the
-  // track.
-  MediaStreamVideoSource* source_;
+  // Weak ref to the source this tracks is connected to.
+  base::WeakPtr<MediaStreamVideoSource> source_;
 
   // This is used for tracking if all connected video sinks are secure.
   SecureDisplayLinkTracker<MediaStreamVideoSink> secure_tracker_;