Fix SDP stream ID mismatch issue when a track's stream changes.

webrtc/media/base/streamparams.h

Index: webrtc/media/base/streamparams.h
diff --git a/webrtc/media/base/streamparams.h b/webrtc/media/base/streamparams.h
index 75d82809cf23cea3e7bced4ca45bebd43a812176..5d7feafbe3eac800545b4738892ad3b471191f78 100644
--- a/webrtc/media/base/streamparams.h
+++ b/webrtc/media/base/streamparams.h
@@ -252,6 +252,13 @@ const StreamParams* GetStream(const StreamParamsVec& streams,
   return found == streams.end() ? nullptr : &(*found);
 }
 
+template <class Condition>
+StreamParams* GetStream(StreamParamsVec& streams, Condition condition) {
+  StreamParamsVec::iterator found =
+      std::find_if(streams.begin(), streams.end(), condition);
+  return found == streams.end() ? nullptr : &(*found);
+}
+
 inline const StreamParams* GetStreamBySsrc(const StreamParamsVec& streams,
                                            uint32_t ssrc) {
   return GetStream(streams,
@@ -261,6 +268,14 @@ inline const StreamParams* GetStreamBySsrc(const StreamParamsVec& streams,
 inline const StreamParams* GetStreamByIds(const StreamParamsVec& streams,
                                           const std::string& groupid,
                                           const std::string& id) {
+  return GetStream(streams, [&groupid, &id](const StreamParams& sp) {
+    return sp.groupid == groupid && sp.id == id;
+  });
+}
+
+inline StreamParams* GetStreamByIds(StreamParamsVec& streams,
+                                    const std::string& groupid,
+                                    const std::string& id) {
   return GetStream(streams,
       [&groupid, &id](const StreamParams& sp) {
         return sp.groupid == groupid && sp.id == id;