Prepare WebRtcVideoReceiveStream for configuration changes.

This is a step in the direction of being able to make configuration
changes without having to tear down and reconstruct the object
during renegotiation.

Bug: none
Change-Id: If594fd41f3a561060f64212c479a25d19adf8598
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/223740
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34402}
diff --git a/call/video_receive_stream.h b/call/video_receive_stream.h
index 61edc88..86e5052 100644
--- a/call/video_receive_stream.h
+++ b/call/video_receive_stream.h
@@ -59,9 +59,13 @@
   // TODO(mflodman) Move all these settings to VideoDecoder and move the
   // declaration to common_types.h.
   struct Decoder {
+    Decoder(SdpVideoFormat video_format, int payload_type);
     Decoder();
     Decoder(const Decoder&);
     ~Decoder();
+
+    bool operator==(const Decoder& other) const;
+
     std::string ToString() const;
 
     SdpVideoFormat video_format;