Revert "[ASCellNode] Fix applyLayoutAttributes not called, add readonly layoutAttributes property (#2321)"

This reverts commit f9ee1dd4b6b4d8a062c5453623bc6fde1840cd91.

This appears to have caused a test failure:
https://travis-ci.org/facebook/AsyncDisplayKit/jobs/164532435

AsyncDisplayKit/ASCellNode+Internal.h

@@ -12,8 +12,6 @@
 
 #import "ASCellNode.h"
 
-NS_ASSUME_NONNULL_BEGIN
-
 @protocol ASCellNodeInteractionDelegate <NSObject>
 
 /**
@@ -51,13 +49,4 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)__setSelectedFromUIKit:(BOOL)selected;
 - (void)__setHighlightedFromUIKit:(BOOL)highlighted;
 
-/**
- * @note This could be declared @c copy, but since this is only settable internally, we can ensure
- *   that it's always safe simply to retain it, and copy if needed. Since @c UICollectionViewLayoutAttributes
- *   is always mutable, @c copy is never "free" like it is for e.g. NSString.
- */
-@property (nonatomic, strong, nullable) UICollectionViewLayoutAttributes *layoutAttributes;
-
 @end
-
-NS_ASSUME_NONNULL_END

AsyncDisplayKit/ASCellNode.h

@@ -74,15 +74,6 @@ typedef NS_ENUM(NSUInteger, ASCellNodeVisibilityEvent) {
  */
 @property (nonatomic, assign) BOOL neverShowPlaceholders;
 
-/*
- * The layout attributes currently assigned to this node, if any.
- *
- * @discussion This property is useful because it is set before @c collectionView:willDisplayNode:forItemAtIndexPath:
- *   is called, when the node is not yet in the hierarchy and its frame cannot be converted to/from other nodes. Instead
- *   you can use the layout attributes object to learn where and how the cell will be displayed.
- */
-@property (nonatomic, strong, readonly, nullable) UICollectionViewLayoutAttributes *layoutAttributes;
-
 /*
  * ASTableView uses these properties when configuring UITableViewCells that host ASCellNodes.
  */

AsyncDisplayKit/ASCellNode.mm

@@ -233,17 +233,6 @@
 
 #pragma clang diagnostic pop
 
-- (void)setLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttributes
-{
-  ASDisplayNodeAssertMainThread();
-  if (ASObjectIsEqual(layoutAttributes, _layoutAttributes) == NO) {
-    _layoutAttributes = layoutAttributes;
-    if (layoutAttributes != nil) {
-      [self applyLayoutAttributes:layoutAttributes];
-    }
-  }
-}
-
 - (void)applyLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttributes
 {
   // To be overriden by subclasses

AsyncDisplayKit/ASCollectionView.mm

@@ -47,15 +47,12 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
 
 @interface _ASCollectionViewCell : UICollectionViewCell
 @property (nonatomic, weak) ASCellNode *node;
-@property (nonatomic, strong) UICollectionViewLayoutAttributes *layoutAttributes;
 @end
 
 @implementation _ASCollectionViewCell
 
 - (void)setNode:(ASCellNode *)node
 {
-  ASDisplayNodeAssertMainThread();
-  node.layoutAttributes = _layoutAttributes;
   _node = node;
   [node __setSelectedFromUIKit:self.selected];
   [node __setHighlightedFromUIKit:self.highlighted];
@@ -75,25 +72,14 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
 
 - (void)prepareForReuse
 {
-  _layoutAttributes = nil;
-  _node.layoutAttributes = nil;
-
   // Need to clear node pointer before UIKit calls setSelected:NO / setHighlighted:NO on its cells
   self.node = nil;
   [super prepareForReuse];
 }
 
-/**
- * In the initial case, this is called by UICollectionView during cell dequeueing, before
- *   we get a chance to assign a node to it, so we must be sure to set these layout attributes
- *   on our node when one is next assigned to us in @c setNode: . Since there may be cases when we _do_ already
- *   have our node assigned e.g. during a layout update for existing cells, we also attempt
- *   to update it now.
- */
 - (void)applyLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttributes
 {
-  _layoutAttributes = layoutAttributes;
-  _node.layoutAttributes = layoutAttributes;
+  [_node applyLayoutAttributes:layoutAttributes];
 }
 
 @end

AsyncDisplayKitTests/ASCollectionViewTests.mm

@@ -22,7 +22,6 @@
 @interface ASTextCellNodeWithSetSelectedCounter : ASTextCellNode
 
 @property (nonatomic, assign) NSUInteger setSelectedCounter;
-@property (nonatomic, assign) NSUInteger applyLayoutAttributesCount;
 
 @end
 
@@ -34,11 +33,6 @@
   _setSelectedCounter++;
 }
 
-- (void)applyLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttributes
-{
-  _applyLayoutAttributesCount++;
-}
-
 @end
 
 @interface ASTestSectionContext : NSObject <ASSectionContext>
@@ -92,16 +86,6 @@
   };
 }
 
-- (void)collectionView:(ASCollectionView *)collectionView willDisplayNode:(ASCellNode *)node forItemAtIndexPath:(NSIndexPath *)indexPath
-{
-  ASDisplayNodeAssertNotNil(node.layoutAttributes, @"Expected layout attributes for node in %@ to be non-nil.", NSStringFromSelector(_cmd));
-}
-
-- (void)collectionView:(ASCollectionView *)collectionView didEndDisplayingNode:(ASCellNode *)node forItemAtIndexPath:(NSIndexPath *)indexPath
-{
-  ASDisplayNodeAssertNotNil(node.layoutAttributes, @"Expected layout attributes for node in %@ to be non-nil.", NSStringFromSelector(_cmd));
-}
-
 - (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
   return _itemCounts.size();
 }
@@ -401,34 +385,6 @@
   } completion:nil]);
 }
 
-- (void)testCellNodeLayoutAttributes
-{
-  updateValidationTestPrologue
-  NSSet *nodeBatch1 = [NSSet setWithArray:[cv visibleNodes]];
-  XCTAssertGreaterThan(nodeBatch1.count, 0);
-
-  // Expect all visible nodes get 1 applyLayoutAttributes and have a non-nil value.
-  for (ASTextCellNodeWithSetSelectedCounter *node in nodeBatch1) {
-    XCTAssertEqual(node.applyLayoutAttributesCount, 1, @"Expected applyLayoutAttributes to be called exactly once for visible nodes.");
-    XCTAssertNotNil(node.layoutAttributes, @"Expected layoutAttributes to be non-nil for visible cell node.");
-  }
-
-  // Scroll to next batch of items.
-  NSIndexPath *nextIP = [NSIndexPath indexPathForItem:nodeBatch1.count inSection:0];
-  [cv scrollToItemAtIndexPath:nextIP atScrollPosition:UICollectionViewScrollPositionTop animated:NO];
-  [cv layoutIfNeeded];
-
-  // Ensure we scrolled far enough that all the old ones are offscreen.
-  NSSet *nodeBatch2 = [NSSet setWithArray:[cv visibleNodes]];
-  XCTAssertFalse([nodeBatch1 intersectsSet:nodeBatch2], @"Expected to scroll far away enough that all nodes are replaced.");
-
-  // Now the nodes are no longer visible, expect their layout attributes are nil but not another applyLayoutAttributes call.
-  for (ASTextCellNodeWithSetSelectedCounter *node in nodeBatch1) {
-    XCTAssertEqual(node.applyLayoutAttributesCount, 1, @"Expected applyLayoutAttributes to be called exactly once for visible nodes, even after node is removed.");
-    XCTAssertNil(node.layoutAttributes, @"Expected layoutAttributes to be nil for removed cell node.");
-  }
-}
-
 /**
  * https://github.com/facebook/AsyncDisplayKit/issues/2011
  *