Merge "Revert "Clean up IMS based interfaces to use a push model instea..."" am: 8827badd30 am: 9a8e4bf6f1 am: a6bc5361b7

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1443078

Change-Id: Icc3add9e3ea4d4a192f6b9e54c68673bc51497d8