Explicitly set default scrollbarstyle value

Summary: Explicitly set default scrollbarstyle value. Previously this style was implicitly used as a side effect of how we set padding on the Scrollview. This instead makes that behavior explicit.

Reviewed By: astreet

Differential Revision: D4386861

fbshipit-source-id: 362d82136a12b75fb81287ac0d0fd58f2ee297fb

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollView.java

@@ -102,6 +102,7 @@ public class ReactScrollView extends ScrollView implements ReactClippingViewGrou
     }
 
     setOnHierarchyChangeListener(this);
+    setScrollBarStyle(SCROLLBARS_OUTSIDE_OVERLAY);
   }
 
   public void setSendMomentumEvents(boolean sendMomentumEvents) {
@@ -380,4 +381,3 @@ public class ReactScrollView extends ScrollView implements ReactClippingViewGrou
     }
   }
 }
-