DO NOT MERGE:  Add status callback for start/stop advertising.

Cherrypick from master to fix b/13289050

Change-Id: I231ba51aaa67b1f917e476ef0f2c8f82c762df77

Conflicts:
	core/java/android/bluetooth/BluetoothAdapter.java
	core/java/android/bluetooth/BluetoothGatt.java
4 files changed