Convert return type of APIs from Set to List.

Most of the time it will either be empty or have 1 device.
Using list makes it much a better API and since its supported
by the AIDL format, the code becomes much nicer.

Change-Id: I5a2508b33ba754fc8cc738409d658e1235aaf2cf
diff --git a/core/java/android/bluetooth/IBluetoothA2dp.aidl b/core/java/android/bluetooth/IBluetoothA2dp.aidl
index c5044c2..b4fc366 100644
--- a/core/java/android/bluetooth/IBluetoothA2dp.aidl
+++ b/core/java/android/bluetooth/IBluetoothA2dp.aidl
@@ -27,9 +27,8 @@
     // Public API
     boolean connect(in BluetoothDevice device);
     boolean disconnect(in BluetoothDevice device);
-    // change to Set<> once AIDL supports
-    BluetoothDevice[] getConnectedDevices();
-    BluetoothDevice[] getDevicesMatchingConnectionStates(in int[] states);
+    List<BluetoothDevice> getConnectedDevices();
+    List<BluetoothDevice> getDevicesMatchingConnectionStates(in int[] states);
     int getConnectionState(in BluetoothDevice device);
     boolean setPriority(in BluetoothDevice device, int priority);
     int getPriority(in BluetoothDevice device);