Remove completely unused layoutManagerDelegate things (#2189)

AsyncDisplayKit/TextKit/ASTextKitAttributes.h

@@ -81,11 +81,6 @@ struct ASTextKitAttributes {
    An array of scale factors in descending order to apply to the text to try to make it fit into a constrained size.
    */
   NSArray *pointSizeScaleFactors;
-  
-  /**
-   An optional delegate for the NSLayoutManager
-   */
-  id<NSLayoutManagerDelegate> layoutManagerDelegate;
 
   /**
    We provide an explicit copy function so we can use aggregate initializer syntax while providing copy semantics for
@@ -105,7 +100,6 @@ struct ASTextKitAttributes {
       shadowOpacity,
       shadowRadius,
       pointSizeScaleFactors,
-      layoutManagerDelegate,
     };
   };