Merge "Expose adhoc conference calling API as public." am: 8ebbe3c038 am: fb8f41f0c2 am: e8a4750ac5 am: bb50f0e74c am: d5be65f281

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1368819

Change-Id: I75f11643c333f69e4e27d72caf8b11f1ce5e5c75