Display recent apps in notification settings

The last 5 non-system apps that have sent notifications
will be displayed at the top level of notification settings for
easy access.

Test: make -j20 RunSettingsRoboTests
Change-Id: Ifaae36f977beb0438a740f61ff0ac9c97f3acc80
Fixes: 63927402

src/com/android/settings/notification/NotificationBackend.java

@@ -27,12 +27,16 @@ import android.content.pm.ParceledListSlice;
 import android.graphics.drawable.Drawable;
 import android.os.ServiceManager;
 import android.os.UserHandle;
+import android.service.notification.NotifyingApp;
 import android.util.IconDrawableFactory;
 import android.util.Log;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.settingslib.Utils;
 
+import java.util.ArrayList;
+import java.util.List;
+
 public class NotificationBackend {
     private static final String TAG = "NotificationBackend";
 
@@ -185,7 +189,6 @@ public class NotificationBackend {
         }
     }
 
-
     public int getDeletedChannelCount(String pkg, int uid) {
         try {
             return sINM.getDeletedChannelCount(pkg, uid);
@@ -204,6 +207,15 @@ public class NotificationBackend {
         }
     }
 
+    public List<NotifyingApp> getRecentApps() {
+        try {
+            return sINM.getRecentNotifyingAppsForUser(UserHandle.myUserId()).getList();
+        } catch (Exception e) {
+            Log.w(TAG, "Error calling NoMan", e);
+            return new ArrayList<>();
+        }
+    }
+
     static class Row {
         public String section;
     }