serria 下，用 chrome 放歌的时候，如何合盖就休眠？

[introom]

serria ，我在 chrome 下听豆瓣，合上盖子，但是不休眠。

我看了一下 pmset -g assertions

2016-11-27 13:41:57 +0800
Assertion status system-wide:
   BackgroundTask                 0
   ApplePushServiceTask           0
   UserIsActive                   1
   PreventUserIdleDisplaySleep    0
   PreventSystemSleep             0
   ExternalMedia                  0
   InternalPreventDisplaySleep    1
   PreventUserIdleSystemSleep     1
   NetworkClientActive            0
Listed by owning process:
   pid 97(hidd): [0x0000b9c500098c06] 00:50:57 UserIsActive named: "com.apple.iohideventsystem.queue.tickle"
        Timeout will fire in 597 secs Action=TimeoutActionRelease
   pid 47(powerd): [0x0000c338001081bf] 00:04:33 InternalPreventDisplaySleep named: "com.apple.powermanagement.delayDisplayOff"
        Timeout will fire in 287 secs Action=TimeoutActionTurnOff
   pid 155(coreaudiod): [0x0000c421000188dd] 00:00:04 PreventUserIdleSystemSleep named: "com.apple.audio.AppleHDAEngineOutput:1F,3,0,1,1:0.context.preventuseridlesleep"
        Created for PID: 508.
   pid 508(Google Chrome): [0x0000c42100018e18] 00:00:04 NoIdleSleepAssertion named: "Playing audio"
No kernel assertions.
Idle sleep preventers: IODisplayWrangler

看上去是 chrome 在组织休眠。 我记得以前系统下合上盖子就不放歌，直接休眠的。 不知道现在怎么设置？

（不光是 chrome ，如果我播放微信的小视频，合上盖子小视频还是在放）