Clean up timing of layout tree flattening/ copying of unflattened tree for Weaver (TextureGroup#1157)

* Simpler Huy fix for more efficient delayed flattening of the layout tree

* Nit

* Remove pbx changes

* Update CHANGELOG.md

* Add note about change in timing of _flattenedLayout capture

Author: mikezucc

CHANGELOG.md

@@ -51,6 +51,7 @@
 - Optimize layout process by removing `ASRectMap`.  [Adlai Holler](https://github.com/Adlai-Holler)
 - Remove necessity to use view to access rangeController in ASTableNode, ASCollectionNode. [Michael Schneider](https://github.com/maicki)
 - Remove display node's reliance on shared_ptr. [Adlai Holler](https://github.com/Adlai-Holler)
+- Clean up timing of layout tree flattening/ copying of unflattened tree for Weaver. [Michael Zuccarino](https://github.com/mikezucc) [#1157](https://github.com/TextureGroup/Texture/pull/1157)
 
 ## 2.7
 - Fix pager node for interface coalescing. [Max Wang](https://github.com/wsdwsd0829) [#877](https://github.com/TextureGroup/Texture/pull/877)

Source/ASDisplayNode+Layout.mm

@@ -993,12 +993,6 @@ - (void)_pendingLayoutTransitionDidComplete
   _pendingLayoutTransition = nil;
 }
 
-- (void)_setCalculatedDisplayNodeLayout:(const ASDisplayNodeLayout &)displayNodeLayout
-{
-  ASDN::MutexLocker l(__instanceLock__);
-  [self _locked_setCalculatedDisplayNodeLayout:displayNodeLayout];
-}
-
 - (void)_locked_setCalculatedDisplayNodeLayout:(const ASDisplayNodeLayout &)displayNodeLayout
 {
   ASAssertLocked(__instanceLock__);
@@ -1007,12 +1001,6 @@ - (void)_locked_setCalculatedDisplayNodeLayout:(const ASDisplayNodeLayout &)disp
   ASDisplayNodeAssertTrue(displayNodeLayout.layout.size.height >= 0.0);
 
   _calculatedDisplayNodeLayout = displayNodeLayout;
-  
-  // Flatten the layout if it wasn't done before (@see -calculateLayoutThatFits:).
-  if ([ASDisplayNode shouldStoreUnflattenedLayouts]) {
-    _unflattenedLayout = _calculatedDisplayNodeLayout.layout; 
-    _calculatedDisplayNodeLayout.layout = [_unflattenedLayout filteredNodeLayoutTree];
-  }
 }
 
 @end

Source/ASDisplayNode.mm

@@ -1220,11 +1220,11 @@ - (ASLayout *)calculateLayoutThatFits:(ASSizeRange)constrainedSize
   }
   ASDisplayNodeLogEvent(self, @"computedLayout: %@", layout);
 
-  // Return the (original) unflattened layout if it needs to be stored. The layout will be flattened later on (@see _locked_setCalculatedDisplayNodeLayout:).
-  // Otherwise, flatten it right away.
-  if (! [ASDisplayNode shouldStoreUnflattenedLayouts]) {
-    layout = [layout filteredNodeLayoutTree];
+  // PR #1157: Reduces accuracy of _unflattenedLayout for debugging/Weaver
+  if ([ASDisplayNode shouldStoreUnflattenedLayouts]) {
+      _unflattenedLayout = layout;
   }
+  layout = [layout filteredNodeLayoutTree];
 
   return layout;
 }