Do not check router's permission on requests from MediaRouter2Manager

In order to allow getting the session creation requests from
MediaRouter2Manager, this CL moves the permission check to inside
requestCreateSessionWithRouter2Locked().

Bug: 153811416
Test: Builds successfully
Change-Id: Ief4b7f4bb73404bcf81427d19e3a753c7d78ec5b

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

@@ -622,6 +622,16 @@ class MediaRouter2ServiceImpl {
             return;
         }
 
+        if (route.isSystemRoute() && !routerRecord.mHasModifyAudioRoutingPermission
+                && !TextUtils.equals(route.getId(),
+                routerRecord.mUserRecord.mHandler.mSystemProvider.getDefaultRoute().getId())) {
+            Slog.w(TAG, "MODIFY_AUDIO_ROUTING permission is required to transfer to"
+                    + route);
+            routerRecord.mUserRecord.mHandler.notifySessionCreationFailedToRouter(
+                    routerRecord, requestId);
+            return;
+        }
+
         long uniqueRequestId = toUniqueRequestId(routerRecord.mRouterId, requestId);
         routerRecord.mUserRecord.mHandler.sendMessage(
                 obtainMessage(UserHandler::requestCreateSessionOnHandler,
@@ -1272,15 +1282,6 @@ class MediaRouter2ServiceImpl {
                         toOriginalRequestId(uniqueRequestId));
                 return;
             }
-            if (route.isSystemRoute() && !routerRecord.mHasModifyAudioRoutingPermission
-                    && !TextUtils.equals(route.getId(),
-                            mSystemProvider.getDefaultRoute().getId())) {
-                Slog.w(TAG, "MODIFY_AUDIO_ROUTING permission is required to transfer to"
-                        + route);
-                notifySessionCreationFailedToRouter(routerRecord,
-                        toOriginalRequestId(uniqueRequestId));
-                return;
-            }
 
             SessionCreationRequest request =
                     new SessionCreationRequest(routerRecord, uniqueRequestId, route, managerRecord);