Merge "[Central Surfaces] Remove unused methods & variables from interface." into udc-qpr-dev am: 1aaaa88ddf am: b24282bd08

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23448832

Change-Id: I746bfff3907abcb36954dd5d87f18a9699cc0e79
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>