Cast: cast_receiver_app to decode audio

Audio decoding in cast_receiver_app stops because it stops calling
GetAudioFrame() if getting one audio frame fails. We should just post
a task every 10ms to keep the loop running.

BUG=347361

Review URL: https://codereview.chromium.org/176883007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253935 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253935