Wait for Bluetooth to be disabled before exiting.

This may have been the cause of Bluetooth not always being disabled at
shutdown on the Sony Xperia Tipo.

briar-android/src/org/briarproject/plugins/droidtooth/DroidtoothPlugin.java

@@ -228,8 +228,18 @@ class DroidtoothPlugin implements DuplexPlugin {
 		tryToClose(socket);
 		// Disable Bluetooth if we enabled it and it's still enabled
 		if(wasDisabled && adapter.isEnabled()) {
-			if(adapter.disable()) LOG.info("Disabling Bluetooth");
-			else LOG.info("Could not disable Bluetooth");
+			// Try to disable the adapter and wait for the result
+			LOG.info("Disabling Bluetooth");
+			IntentFilter filter = new IntentFilter(ACTION_STATE_CHANGED);
+			DisableBluetoothReceiver receiver = new DisableBluetoothReceiver();
+			appContext.registerReceiver(receiver, filter);
+			if(adapter.disable()) {
+				LOG.info("Disabling Bluetooth");
+				receiver.waitForStateChange();
+			} else {
+				LOG.info("Could not disable Bluetooth");
+			}
+			appContext.unregisterReceiver(receiver);
 		}
 	}
 
@@ -382,6 +392,28 @@ class DroidtoothPlugin implements DuplexPlugin {
 		}
 	}
 
+	private class DisableBluetoothReceiver extends BroadcastReceiver {
+
+		private final CountDownLatch latch = new CountDownLatch(1);
+
+		public void onReceive(Context ctx, Intent intent) {
+			int state = intent.getIntExtra(EXTRA_STATE, 0);
+			if(state == STATE_OFF) {
+				LOG.info("Bluetooth disabled");
+				latch.countDown();
+			}
+		}
+
+		private void waitForStateChange() {
+			try {
+				latch.await();
+			} catch(InterruptedException e) {
+				LOG.info("Interrupted while disabling Bluetooth");
+				Thread.currentThread().interrupt();
+			}
+		}
+	}
+
 	private class DiscoveryThread extends Thread {
 
 		private final LatchedReference<BluetoothSocket> socketLatch;