Enable RL sync by default on iOS

chrome/browser/sync/chrome_sync_client.cc

Index: chrome/browser/sync/chrome_sync_client.cc
diff --git a/chrome/browser/sync/chrome_sync_client.cc b/chrome/browser/sync/chrome_sync_client.cc
index 2486d7cc19b6f95f8c1b11c4a652c1a845a39654..00281a541b3d688ad2a5a879e0641c17d34efc8f 100644
--- a/chrome/browser/sync/chrome_sync_client.cc
+++ b/chrome/browser/sync/chrome_sync_client.cc
@@ -436,6 +436,10 @@ ChromeSyncClient::GetSyncBridgeForModelType(syncer::ModelType type) {
       return ProfileSyncServiceFactory::GetForProfile(profile_)
           ->GetDeviceInfoSyncBridge()
           ->AsWeakPtr();
+    case syncer::READING_LIST:
+      // Reading List is only supported on iOS at the moment.
+      NOTREACHED();
+      return base::WeakPtr<syncer::ModelTypeSyncBridge>();
     default:
       NOTREACHED();
       return base::WeakPtr<syncer::ModelTypeSyncBridge>();