Merge "Camera: Improve documentation for 3A regions" into tm-dev am: 7af7fcbe

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17450512



Change-Id: Ife6814c6f0906c820b7570052f616cb0083325cb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>