Merge "Support for showing percent progress in boot animation." am: 87d840addd am: b86c3a3470

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1545805

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ic4b699c54e725f6bde23d9f0123536bd2f0d6366