迟迟等不到官方的更新通知，就自己下载ota档sideload update了
Android O brings picture-in-picture support so you can watch YouTube while
hailing a Lyft 这篇文中（https://goo.gl/21QGc1）有提到：
“Picture-in-picture is just one of the handful of new features that come with
Android O today. Compatible devices for the preview include the Nexus 5X,
Nexus 6P, Nexus Player, Pixel, Pixel XL, and Pixel C.”
在设定里头也有确定picture in picture有开启
开了两个app来测试（hangouts, youtube）
想试验边用hangouts边用picture in picture 看youtube的情景
在切换的视窗没看到东西
在Youtube的视窗也是
试过单点、双点recent, home, back 都失败
有人有用nexus 5x 试成功吗？