Merge "Fix extra transition animation played after back gesture trigger." into...

Merge "Fix extra transition animation played after back gesture trigger." into udc-dev am: 58aab277 am: 8b2da2e9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22240772



Change-Id: I43d6d846d134a80f8145bdeaa6ee5399ac461497
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>