Fork v4 support library NestedScrollView to fix fling bug

Reviewed By: oli, lexs

Differential Revision: D2707733

fb-gh-sync-id: c9b375a6aa1010d60d21ca7500e862a6ff91a49b

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

@@ -24,7 +24,7 @@ public class ReactScrollViewHelper {
   /**
    * Shared by {@link ReactScrollView} and {@link ReactHorizontalScrollView}.
    */
-  /* package */ static void emitScrollEvent(ViewGroup scrollView, int scrollX, int scrollY) {
+  public static void emitScrollEvent(ViewGroup scrollView, int scrollX, int scrollY) {
     View contentView = scrollView.getChildAt(0);
     ReactContext reactContext = (ReactContext) scrollView.getContext();
     reactContext.getNativeModule(UIManagerModule.class).getEventDispatcher().dispatchEvent(

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

@@ -81,6 +81,10 @@ public class ReactScrollViewManager
 
   @Override
   public @Nullable Map getExportedCustomDirectEventTypeConstants() {
+    return createExportedCustomDirectEventTypeConstants();
+  }
+
+  public static Map createExportedCustomDirectEventTypeConstants() {
     return MapBuilder.builder()
         .put(ScrollEvent.EVENT_NAME, MapBuilder.of("registrationName", "onScroll"))
         .put("topScrollBeginDrag", MapBuilder.of("registrationName", "onScrollBeginDrag"))