Merge "Try to fix IndexOutBoundsException in Task#removeChild" into rvc-dev am: e938c572b7 am: 57f60c236d

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11836345

Change-Id: I48f7ea35f3514c2748fb9ea7a6713c2baf8e550f