Add @RequiresPermission annotation to SystemApis in BluetoothPan, open
up close method as a SystemApi, and BluetoothPan class now implements
AutoCloseable and CloseGuard

Bug: 146045934
Test: Manual
Change-Id: Iafb2157d67ae4f8e3d7d97cf4198f2978e391a8c
2 files changed