[Android] Extract MediaSessionCallback from PlaybackService

[Geoffrey Métais]

vlc-android | branch: master | Geoffrey Métais <geoffrey.metais at gmail.com> | Mon Apr 16 14:24:51 2018 +0200| [41ab7aefa0ad6b026e4f8cdfa776fcaed81cb4e2] | committer: Geoffrey Métais

Extract MediaSessionCallback from PlaybackService

> https://code.videolan.org/videolan/vlc-android/commit/41ab7aefa0ad6b026e4f8cdfa776fcaed81cb4e2
---

 .../src/org/videolan/vlc/MediaSessionCallback.kt   | 179 ++++++++++++++++++++
 .../src/org/videolan/vlc/PlaybackService.kt        | 183 ++-------------------
 2 files changed, 189 insertions(+), 173 deletions(-)

Diff:   https://code.videolan.org/videolan/vlc-android/commit/41ab7aefa0ad6b026e4f8cdfa776fcaed81cb4e2