MediaRouter: Returning unmodifiable list for internal data

Previously, get{Member,Unselectable,Transferable,Groupable}Routes()
just returned the internal data, which are mutable list of routes.
This CL protects internal data by making it read-only for callers.

Test: ./gradlew :mediarouter:connectedCheck
Change-Id: I8a7682fbef3cfd217a7889b9035f9d0901ec1eee

1 files changed, 5 insertions, 5 deletions

diff --git a/mediarouter/src/main/java/androidx/mediarouter/media/MediaRouter.java b/mediarouter/src/main/java/androidx/mediarouter/media/MediaRouter.java
index 6aa6c9405a8..ca80c6d7af7 100644
--- a/mediarouter/src/main/java/androidx/mediarouter/media/MediaRouter.java
+++ b/mediarouter/src/main/java/androidx/mediarouter/media/MediaRouter.java
@@ -1681,7 +1681,7 @@ public final class MediaRouter {
          * @return The list of the routes in this group
          */
         public List<RouteInfo> getMemberRoutes() {
-            return mMemberRoutes;
+            return Collections.unmodifiableList(mMemberRoutes);
         }
 
         @Override
@@ -1786,15 +1786,15 @@ public final class MediaRouter {
         }
 
         public List<RouteInfo> getUnselectableRoutes() {
-            return mUnselectableRoutes;
+            return Collections.unmodifiableList(mUnselectableRoutes);
         }
 
         public List<RouteInfo> getGroupableRoutes() {
-            return mGroupableRoutes;
+            return Collections.unmodifiableList(mGroupableRoutes);
         }
 
         public List<RouteInfo> getTransferableRoutes() {
-            return mTransferableRoutes;
+            return Collections.unmodifiableList(mTransferableRoutes);
         }
 
         /**
@@ -1859,7 +1859,7 @@ public final class MediaRouter {
          */
         public List<RouteInfo> getRoutes() {
             checkCallingThread();
-            return mRoutes;
+            return Collections.unmodifiableList(mRoutes);
         }
 
         Resources getResources() {