Enable passing receive stream ID to the decoder factory.

webrtc/media/engine/webrtcvideoengine2.cc

Index: webrtc/media/engine/webrtcvideoengine2.cc
diff --git a/webrtc/media/engine/webrtcvideoengine2.cc b/webrtc/media/engine/webrtcvideoengine2.cc
index f32749199f90e6d67218c381beedb3ef30174931..225ac80584c7521917083ec0760eefecd8e94448 100644
--- a/webrtc/media/engine/webrtcvideoengine2.cc
+++ b/webrtc/media/engine/webrtcvideoengine2.cc
@@ -2252,6 +2252,7 @@ WebRtcVideoChannel2::WebRtcVideoReceiveStream::GetSsrcs() const {
 
 WebRtcVideoChannel2::WebRtcVideoReceiveStream::AllocatedDecoder
 WebRtcVideoChannel2::WebRtcVideoReceiveStream::CreateOrReuseVideoDecoder(
+    uint32_t ssrc,
     std::vector<AllocatedDecoder>* old_decoders,
     const VideoCodec& codec) {
   webrtc::VideoCodecType type = CodecTypeFromName(codec.name);
@@ -2267,7 +2268,7 @@ WebRtcVideoChannel2::WebRtcVideoReceiveStream::CreateOrReuseVideoDecoder(
 
   if (external_decoder_factory_ != NULL) {
     webrtc::VideoDecoder* decoder =
-        external_decoder_factory_->CreateVideoDecoder(type);
+        external_decoder_factory_->CreateVideoDecoderForSsrc(ssrc, type);
     if (decoder != NULL) {
       return AllocatedDecoder(decoder, type, true);
     }
@@ -2300,8 +2301,9 @@ void WebRtcVideoChannel2::WebRtcVideoReceiveStream::ConfigureCodecs(
   allocated_decoders_.clear();
   config_.decoders.clear();
   for (size_t i = 0; i < recv_codecs.size(); ++i) {
+    uint32_t ssrc = ssrcs_.empty() ? 0 : ssrcs_[0];
     AllocatedDecoder allocated_decoder =
-        CreateOrReuseVideoDecoder(old_decoders, recv_codecs[i].codec);
+        CreateOrReuseVideoDecoder(ssrc, old_decoders, recv_codecs[i].codec);
     allocated_decoders_.push_back(allocated_decoder);
 
     webrtc::VideoReceiveStream::Decoder decoder;