OS: android/chromecast

What steps will reproduce the problem?
(1) play lots of different audio streams (e.g. the blip sound on volume change, or the duo "call connected" SFX.
*Repro rate is relatively low, however I can hit the bug (maybe once/15-30mins) by casting Play Music from a phone, pausing the audio, and holding/dragging the volume slider.

What is the expected result?
Nobody should be able to call into the callback when not started.

What happens instead?
OnError() is called, which causes a segfault on source_callback_


Worked prior to c9c6de7f90cbe250211913db243bde16c857ea84, which is not directly to blame but merely affected audio stream timing which exacerbated this threading issue (at least on slow devices).


logging::LogMessage::~LogMessage()
media::OnMoreDataConverter::OnError()
chromecast::media::CastAudioOutputStream::CmaWrapper::Start(media::AudioOutputStream::AudioSourceCallback*)