Enable passing receive stream ID to the decoder factory.

webrtc/video_decoder.h

Index: webrtc/video_decoder.h
diff --git a/webrtc/video_decoder.h b/webrtc/video_decoder.h
index 4f25e1fdce54436acec09d5d81a89cc72cfc0be5..db0495ed97b54eee6494da5e452eda8f3eb0ddb6 100644
--- a/webrtc/video_decoder.h
+++ b/webrtc/video_decoder.h
@@ -81,6 +81,10 @@ class VideoDecoder {
   virtual bool PrefersLateDecoding() const { return true; }
 
   virtual const char* ImplementationName() const { return "unknown"; }
+
+  // Some VideoDecoders may choose to override this to return SSRC of the
+  // stream. Otherwise, returns 0.
+  virtual uint32_t ssrc() const { return 0; }

[perkj_webrtc, 2016/06/10 13:22:20]

please remove from the interface.

[sakal, 2016/06/14 13:28:44]

Done.

[noahric, 2016/06/14 17:51:10]

See my comment elsewhere; if receive streams can have multiple ssrcs, then you
need to keep this so the allocate-or-reuse can make sure to keep the ssrcs
consistent.

(Or if the ssrc can change through an allocate-or-reuse point)

 };
 
 // Class used to wrap external VideoDecoders to provide a fallback option on