Merge "Expose Phone.ENTERPRISE_CONTENT_URI as systemApi" into stage-aosp-master am: f2753ce65f am: 984f8fcc51

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15934185

Change-Id: I54ac1cd2ebae0d7d32fd16323b4b414fbb9f50eb