Merge "Merge "Simplify synchronized code and add comments" am: 9791b54b am:...

Merge "Merge "Simplify synchronized code and add comments" am: 9791b54b am: b57f32e6 am: 9760c427 am: ddf2351c" into rvc-qpr-dev-plus-aosp am: 9d976f06

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1416212

Change-Id: I69b9b2ae48574395e616061093c21e5ea3641570