Merge "Keystore 2.0: Add @IntDef for Keystore namespaces." am: faabd1a836 am: 15d9a3ab42 am: a32dc0fbe2

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1649668

Change-Id: I9059f8c84bf57ea2668ea1209d2a2125796bb178