bluetooth: android: register for adapter on/off events.

device/bluetooth/bluetooth_adapter.h

Index: device/bluetooth/bluetooth_adapter.h
diff --git a/device/bluetooth/bluetooth_adapter.h b/device/bluetooth/bluetooth_adapter.h
index e099e32d12bdc4e98aaecb46f6412bc73fa26739..5dcf12f54bd9104841fab75bb62fed94b0ffb951 100644
--- a/device/bluetooth/bluetooth_adapter.h
+++ b/device/bluetooth/bluetooth_adapter.h
@@ -398,8 +398,8 @@ class DEVICE_BLUETOOTH_EXPORT BluetoothAdapter
       const CreateAdvertisementCallback& callback,
       const CreateAdvertisementErrorCallback& error_callback) = 0;
 
-  // The following methods are used to send various GATT observer events to
-  // observers.
+  // The following methods are used to send various events to observers.
+  void NotifyAdapterStateChanged(bool powered);
   void NotifyGattServiceAdded(BluetoothGattService* service);
   void NotifyGattServiceRemoved(BluetoothGattService* service);
   void NotifyGattServiceChanged(BluetoothGattService* service);