Merge "Make BluetoothGattCallback.onServiceChanged public" am: 802503736d am: 531993dca1 am: 23c923d197 am: 41e6915dcd

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1439193

Change-Id: Id9945a11865c9e4ae0155eccc19cbbdc90dd5d48