Merge "Keystore 2.0: Add keystore engine grant string convenience functions." am: 4da629d9be

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1569501

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ibe70ce5d83ea20a85af2817d8e491e932d9c49f1