Merge "Remove root layer when clearing mLayersPendingRemoval" into tm-dev am: b089aa579f am: 0da4fbd671 am: b92f0b82d6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/17837364

Change-Id: I2228d68dcf2e4b7943626d37c92b4a4a6c5da503
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>