use .contains

Reviewed By: achen1

Differential Revision: D5242469

fbshipit-source-id: d666b1264e6e40bb2649ab91bc63ecb6decb1532

ReactAndroid/src/main/java/com/facebook/react/bridge/ReactMarker.java

@@ -28,7 +28,7 @@ public class ReactMarker {
   @DoNotStrip
   public static void addListener(MarkerListener listener) {
     synchronized(sListeners) {
-      if (sListeners.indexOf(listener) == -1) {
+      if (!sListeners.contains(listener)) {
         sListeners.add(listener);
       }
     }