MSE: Remap single text track number changes in frame processor

media/filters/chunk_demuxer.cc

Index: media/filters/chunk_demuxer.cc
diff --git a/media/filters/chunk_demuxer.cc b/media/filters/chunk_demuxer.cc
index 3341fcc86bc53bd80d9500c1dca93a32cc807a42..f23e5340616b8a8339434b431a50dd64cad5bcdc 100644
--- a/media/filters/chunk_demuxer.cc
+++ b/media/filters/chunk_demuxer.cc
@@ -623,8 +623,17 @@ bool SourceState::OnNewConfigs(
         success &= false;
         MEDIA_LOG(log_cb_) << "New text track config does not match old one.";
       } else {
-        text_stream_map_.clear();
-        text_stream_map_[config_itr->first] = text_stream;
+        StreamParser::TrackId old_id = stream_itr->first;
+        StreamParser::TrackId new_id = config_itr->first;
+        if (new_id != old_id) {
+          if (frame_processor_->UpdateTrack(old_id, new_id)) {
+            text_stream_map_.clear();
+            text_stream_map_[config_itr->first] = text_stream;
+          } else {
+            success &= false;
+            MEDIA_LOG(log_cb_) << "Error remapping single text track number";
+          }
+        }
       }
     } else {
       for (TextConfigItr config_itr = text_configs.begin();