Mediaplayer playback pauses if it's unfocused

[TarotChen]

current build number: 14
device name: frieza
channel: ubuntu-touch/rc/bq-aquaris-pd.en
last update: 2016-05-25 13:04:23
version version: 14
version ubuntu: 20160524.1
version device: 20160523.0
version custom: 20160511--40-9-vivid

Steps:
1.Connect DUT with external monitor, BT mouse and BT keyboard to enable windowed mode
2.Play tracks in music app
3.Move cursor to the right edge of screen and select another app from switcher
4.Play video in media app
5.Move cursor to the right edge of screen and select another app from switcher

Actual:
At step3, tracks continue playing when music app is unfocused.
At step5, video playback pauses when media app is unfocused

Expected result:
Apps stay active even if they are unfocused