Fix on demand mounting in RTL

Summary:
Changelog: [internal]

When calculating on demand views, RTL layout needs to be considered.

Reviewed By: JoshuaGross

Differential Revision: D28510293

fbshipit-source-id: 5e7b08fcc5c55fa1a978024a9bfedda705ce1702

React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm

@@ -622,10 +622,11 @@ - (void)_remountChildren
     return;
   }
 
-  CGRect visibleFrame = CGRect{_scrollView.contentOffset, _scrollView.bounds.size};
+  CGRect visibleFrame = [_scrollView convertRect:_scrollView.bounds toView:_containerView];
   visibleFrame = CGRectInset(visibleFrame, -kClippingLeeway, -kClippingLeeway);
 
-  CGFloat scale = 1.0 / _scrollView.zoomScale;
+  // `zoomScale` is negative in RTL. Absolute value is needed.
+  CGFloat scale = 1.0 / std::abs(_scrollView.zoomScale);
   visibleFrame.origin.x *= scale;
   visibleFrame.origin.y *= scale;
   visibleFrame.size.width *= scale;