Ranker --> Assistant.

Rename ranker to assistant and make some of the methods public.
Delete the ext services ranker and restore the listener-type
lifecycle to the assistant.

Test: manual. add a notification assistant and verify it gets
assistant and listener callbacks.

Change-Id: Ia3406c8c14d923426c1b8a6d8b5187efe64c31c3
diff --git a/compiled-classes-phone b/compiled-classes-phone
index 8428e41..33e3e04 100644
--- a/compiled-classes-phone
+++ b/compiled-classes-phone
@@ -3610,9 +3610,9 @@
 android.service.notification.NotificationListenerService$Ranking
 android.service.notification.NotificationListenerService$RankingMap
 android.service.notification.NotificationListenerService$RankingMap$1
-android.service.notification.NotificationRankerService
-android.service.notification.NotificationRankerService$MyHandler
-android.service.notification.NotificationRankerService$NotificationRankingServiceWrapper
+android.service.notification.NotificationAssistantService
+android.service.notification.NotificationAssistantService$MyHandler
+android.service.notification.NotificationAssistantService$NotificationRankingServiceWrapper
 android.service.notification.NotificationRankingUpdate
 android.service.notification.NotificationRankingUpdate$1
 android.service.notification.StatusBarNotification