Clear preferred feature when unregistering MediaRouter2

MediaRouter2Managers' preferred feature didn't get cleared even when the
MediaRouter2 is unregistered/died. As a result, when an app is
reinstalled/relaunched, the routes for the previous process are still
shown in the MediaRouter2Manager.

This CL fixes the problem.

Bug: 158824569
Test: Passed CTS and mediaroutertest
      Also tested with reinstalling support7Demos.
Change-Id: Ib5d84c41862177af32931e0d69b02f461105bba6

media/java/android/media/MediaRouter2Manager.java

@@ -576,6 +576,10 @@ public final class MediaRouter2Manager {
     }
 
     void updatePreferredFeatures(String packageName, List<String> preferredFeatures) {
+        if (preferredFeatures == null) {
+            mPreferredFeaturesMap.remove(packageName);
+            return;
+        }
         List<String> prevFeatures = mPreferredFeaturesMap.put(packageName, preferredFeatures);
         if ((prevFeatures == null && preferredFeatures.size() == 0)
                 || Objects.equals(preferredFeatures, prevFeatures)) {

services/core/java/com/android/server/media/MediaRouter2ServiceImpl.java

@@ -598,6 +598,10 @@ class MediaRouter2ServiceImpl {
 
         UserRecord userRecord = routerRecord.mUserRecord;
         userRecord.mRouterRecords.remove(routerRecord);
+        routerRecord.mUserRecord.mHandler.sendMessage(
+                obtainMessage(UserHandler::notifyPreferredFeaturesChangedToManagers,
+                        routerRecord.mUserRecord.mHandler,
+                        routerRecord.mPackageName, /* preferredFeatures=*/ null));
         userRecord.mHandler.sendMessage(
                 obtainMessage(UserHandler::updateDiscoveryPreferenceOnHandler,
                         userRecord.mHandler));
@@ -613,7 +617,9 @@ class MediaRouter2ServiceImpl {
         routerRecord.mDiscoveryPreference = discoveryRequest;
         routerRecord.mUserRecord.mHandler.sendMessage(
                 obtainMessage(UserHandler::notifyPreferredFeaturesChangedToManagers,
-                        routerRecord.mUserRecord.mHandler, routerRecord));
+                        routerRecord.mUserRecord.mHandler,
+                        routerRecord.mPackageName,
+                        routerRecord.mDiscoveryPreference.getPreferredFeatures()));
         routerRecord.mUserRecord.mHandler.sendMessage(
                 obtainMessage(UserHandler::updateDiscoveryPreferenceOnHandler,
                         routerRecord.mUserRecord.mHandler));
@@ -1954,7 +1960,8 @@ class MediaRouter2ServiceImpl {
             }
         }
 
-        private void notifyPreferredFeaturesChangedToManagers(@NonNull RouterRecord routerRecord) {
+        private void notifyPreferredFeaturesChangedToManagers(@NonNull String routerPackageName,
+                @Nullable List<String> preferredFeatures) {
             MediaRouter2ServiceImpl service = mServiceRef.get();
             if (service == null) {
                 return;
@@ -1967,8 +1974,7 @@ class MediaRouter2ServiceImpl {
             }
             for (IMediaRouter2Manager manager : managers) {
                 try {
-                    manager.notifyPreferredFeaturesChanged(routerRecord.mPackageName,
-                            routerRecord.mDiscoveryPreference.getPreferredFeatures());
+                    manager.notifyPreferredFeaturesChanged(routerPackageName, preferredFeatures);
                 } catch (RemoteException ex) {
                     Slog.w(TAG, "Failed to notify preferred features changed."
                             + " Manager probably died.", ex);