Remove deprecated nativeScrollDelegate property

Summary: We deprecated it a while back and nobody is using it internally.

Reviewed By: majak

Differential Revision: D3542602

fbshipit-source-id: dfe11a47b21d2f8a7c946c902f0ea427615ffc31

React/Views/RCTScrollView.m

@@ -383,8 +383,6 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
   NSHashTable *_scrollListeners;
 }
 
-@synthesize nativeScrollDelegate = _nativeScrollDelegate;
-
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher
 {
   RCTAssertParam(eventDispatcher);
@@ -588,19 +586,6 @@ for (NSObject<UIScrollViewDelegate> *scrollViewListener in _scrollListeners) { \
 RCT_SCROLL_EVENT_HANDLER(scrollViewWillBeginDecelerating, onMomentumScrollBegin)
 RCT_SCROLL_EVENT_HANDLER(scrollViewDidZoom, onScroll)
 
-- (void)setNativeScrollDelegate:(NSObject<UIScrollViewDelegate> *)nativeScrollDelegate
-{
-  if (nativeScrollDelegate != _nativeScrollDelegate) {
-    if (_nativeScrollDelegate) {
-      [_scrollListeners removeObject:_nativeScrollDelegate];
-    }
-    if (nativeScrollDelegate) {
-      [_scrollListeners addObject:nativeScrollDelegate];
-    }
-    _nativeScrollDelegate = nativeScrollDelegate;
-  }
-}
-
 - (void)addScrollListener:(NSObject<UIScrollViewDelegate> *)scrollListener
 {
   [_scrollListeners addObject:scrollListener];
@@ -608,11 +593,7 @@ RCT_SCROLL_EVENT_HANDLER(scrollViewDidZoom, onScroll)
 
 - (void)removeScrollListener:(NSObject<UIScrollViewDelegate> *)scrollListener
 {
-  if (scrollListener == _nativeScrollDelegate) {
-    [self setNativeScrollDelegate:nil];
-  } else {
-    [_scrollListeners removeObject:scrollListener];
-  }
+  [_scrollListeners removeObject:scrollListener];
 }
 
 - (void)scrollViewDidScroll:(UIScrollView *)scrollView

React/Views/RCTScrollableProtocol.h

@@ -15,10 +15,6 @@
  */
 @protocol RCTScrollableProtocol
 
-/*
- * The nativeScrollDelegate property is now deprecated please use the scrollListener API instead
- */
-@property (nonatomic, weak) NSObject<UIScrollViewDelegate> *nativeScrollDelegate DEPRECATED_ATTRIBUTE;
 @property (nonatomic, readonly) CGSize contentSize;
 
 - (void)scrollToOffset:(CGPoint)offset;