[Android] Video player: fix subtitles lost on multitasking

[Geoffrey Métais]

vlc-android | branch: master | Geoffrey Métais <geoffrey.metais at gmail.com> | Thu Jun 13 11:56:58 2019 +0200| [64ab60ed87dae79fb03d0b1f5c8bffb0f61746de] | committer: Geoffrey Métais

Video player: fix subtitles lost on multitasking

Also, some code cleaning following Kotlin conversion

> https://code.videolan.org/videolan/vlc-android/commit/64ab60ed87dae79fb03d0b1f5c8bffb0f61746de
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 .../videolan/vlc/gui/video/VideoPlayerActivity.kt  | 149 +++++++++++----------
 1 file changed, 75 insertions(+), 74 deletions(-)

Diff:   https://code.videolan.org/videolan/vlc-android/commit/64ab60ed87dae79fb03d0b1f5c8bffb0f61746de