Historical notification access API.

Similar to getActiveNotifications(),
getHistoricalNotifications() returns a list of all
notifications that have been posted, in
reverse-chronological order. It currently includes duplicate
entries for notifications that have been updated (so it
really is tracking every notification that has been posted
to the system).

Change-Id: Icce8d6f96bbe76710c989fd0068ff971c6498605
diff --git a/core/java/android/app/INotificationManager.aidl b/core/java/android/app/INotificationManager.aidl
index bb10f62..1f4c81d 100644
--- a/core/java/android/app/INotificationManager.aidl
+++ b/core/java/android/app/INotificationManager.aidl
@@ -38,5 +38,6 @@
     boolean areNotificationsEnabledForPackage(String pkg, int uid);
 
     StatusBarNotification[] getActiveNotifications(String callingPkg);
+    StatusBarNotification[] getHistoricalNotifications(String callingPkg, int count);
 }