Merge "Merge "Mark implicit PendingIntents as immutable" into rvc-dev am:...

Merge "Merge "Mark implicit PendingIntents as immutable" into rvc-dev am: e35ad478 am: a64978fe am: 54d2facd" into rvc-qpr-dev-plus-aosp am: 89fd0e93

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/12296407

Change-Id: Ib16f8f65215f62a59f5794c315dd6f9a9ab53767