Allow muting/unmuting audio through media track API

media/test/pipeline_integration_test_base.cc

Index: media/test/pipeline_integration_test_base.cc
diff --git a/media/test/pipeline_integration_test_base.cc b/media/test/pipeline_integration_test_base.cc
index 17647ba7ad07dd725c6998ae55f1864f348b398b..a27717757c7805396a49ef48d867e5bf61834d63 100644
--- a/media/test/pipeline_integration_test_base.cc
+++ b/media/test/pipeline_integration_test_base.cc
@@ -83,6 +83,10 @@ void PipelineIntegrationTestBase::DemuxerEncryptedMediaInitDataCB(
 void PipelineIntegrationTestBase::DemuxerMediaTracksUpdatedCB(
     scoped_ptr<MediaTracks> tracks) {
   CHECK(tracks);
+  CHECK(demuxer_);
+  for (const auto& track : tracks->tracks()) {
+    demuxer_->OnTrackIdAssigned(++track_id_, track.get());
+  }
 }
 
 void PipelineIntegrationTestBase::OnEnded() {
@@ -273,16 +277,14 @@ void PipelineIntegrationTestBase::CreateDemuxer(
     scoped_ptr<DataSource> data_source) {
   data_source_ = std::move(data_source);
 
-  Demuxer::MediaTracksUpdatedCB tracks_updated_cb =
-      base::Bind(&PipelineIntegrationTestBase::DemuxerMediaTracksUpdatedCB,
-                 base::Unretained(this));
-
 #if !defined(MEDIA_DISABLE_FFMPEG)
   demuxer_ = scoped_ptr<Demuxer>(new FFmpegDemuxer(
       message_loop_.task_runner(), data_source_.get(),
       base::Bind(&PipelineIntegrationTestBase::DemuxerEncryptedMediaInitDataCB,
                  base::Unretained(this)),
-      tracks_updated_cb, new MediaLog()));
+      base::Bind(&PipelineIntegrationTestBase::DemuxerMediaTracksUpdatedCB,
+                 base::Unretained(this)),
+      new MediaLog()));
 #endif
 }