Add a VR listener service.

Bug: 22855417
Bug: 26724891
Bug: 27364145

- Add an API for VrListenerService, which is bound/unbound
  from the framework when the system VR mode changes.
- Allow only a single bound VrListenerService at a time.
- Monitor allowed VrListenerService implementations from
  VrManagerService and evict services as needed when packages,
  users, or settings change.
- Remove previous VR functionality in NotificationListenerService.
- Add component target to Activity#setVrMode to allow
  explicit selection of the running VrListenerService from
  the current VR activity.

Change-Id: I776335f4441be0e793d3126f2d16faf86a8c621a
diff --git a/Android.mk b/Android.mk
index 3ac5889..44c88a0 100644
--- a/Android.mk
+++ b/Android.mk
@@ -241,6 +241,7 @@
 	core/java/android/service/notification/IStatusBarNotificationHolder.aidl \
 	core/java/android/service/notification/IConditionListener.aidl \
 	core/java/android/service/notification/IConditionProvider.aidl \
+	core/java/android/service/vr/IVrListener.aidl \
 	core/java/android/print/ILayoutResultCallback.aidl \
 	core/java/android/print/IPrinterDiscoveryObserver.aidl \
 	core/java/android/print/IPrintDocumentAdapter.aidl \