Implement disabling and enabling media tracks

chromecast/media/cma/base/demuxer_stream_for_test.cc

Index: chromecast/media/cma/base/demuxer_stream_for_test.cc
diff --git a/chromecast/media/cma/base/demuxer_stream_for_test.cc b/chromecast/media/cma/base/demuxer_stream_for_test.cc
index 32ee27b0fe1c8b9b50593b13f1fc00f8e1f496f3..13e426b4a85c81ceca15867ce1a41522e3c249ad 100644
--- a/chromecast/media/cma/base/demuxer_stream_for_test.cc
+++ b/chromecast/media/cma/base/demuxer_stream_for_test.cc
@@ -78,6 +78,14 @@ bool DemuxerStreamForTest::SupportsConfigChanges() {
   return ::media::VIDEO_ROTATION_0;
 }
 
+bool DemuxerStreamForTest::enabled() const {
+  return true;
+}
+
+void DemuxerStreamForTest::set_enabled(bool enabled, base::TimeDelta time) {
+  NOTIMPLEMENTED();
+}
+
 void DemuxerStreamForTest::DoRead(const ReadCB& read_cb) {
   has_pending_read_ = false;