When the user selects a "Silent" notification sound, the Uri encoded
path is an empty string. Setting this Uri as the data source of the
MediaPlayer used to play notifications caused the completion listener
to not be called, which with the AudioFocus logic causes the Music
app to pause and never resume. The NotificationPlayer modifications
cause the MediaPlayer for the notification to only request audio
focus when the data source is not empty.
The audio focus code in AudioService is defensively synchronized
against a unique lock, and the exception observed in bug 2670395
is explicitely caught in case another edge case wasn't caught by
this fix.
The AudioFocus handling in AudioManager is modified so only the
requestAudioFocus and abandonAudioFocus methods are meant to be
used, as registerAudioFocusListener and unregisterAudioFocusListener
provided no additional functionality over the request/abandon
methods. abandonAudioFocus() also removes the listener from the
map in AudioManager since after abandonning focus, the listener
would no longer be called.
Change-Id: I3b553ee8a8163c25e01117d7e5479dd5fdfa7c6b
392a2bbb52