Render inband text tracks in the media pipeline

media/base/mock_demuxer_host.cc

Index: media/base/mock_demuxer_host.cc
diff --git a/media/base/mock_demuxer_host.cc b/media/base/mock_demuxer_host.cc
index 100787f23af92bd97debd5254a05efe2f28fabb7..ab045bd109af5151f8278872592bfcdbea9090fd 100644
--- a/media/base/mock_demuxer_host.cc
+++ b/media/base/mock_demuxer_host.cc
@@ -10,4 +10,15 @@ MockDemuxerHost::MockDemuxerHost() {}
 
 MockDemuxerHost::~MockDemuxerHost() {}
 
+void MockDemuxerHost::AddTextStream(DemuxerStream* text_stream,
+                                    TextKind kind,
+                                    const std::string& label,
+                                    const std::string& language) {
+  text_streams_[text_stream] = TextTrackConfig(kind, label, language);
+}
+
+void MockDemuxerHost::RemoveTextStream(DemuxerStream* text_stream) {
+  text_streams_.erase(text_stream);
+}
+
 }  // namespace media