Fabric: Removing LayoutContext::absolutePosition

Summary:
Here is why:
	* It was with us from the very beginning but we never use it.
	* The main purpose of this - snap-to-pixel layout - was moved to Yoga, where it should be.
	* The current implementation has a bug.
	* It's not really correct conceptually because the value becomes incorrect when an immutable subtree is being reused as part of a new tree.
	* It over-complicates a new feature I am working on.

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: sammy-SC

Differential Revision: D22284645

fbshipit-source-id: c4c2df8d24e8fe924725b465e04e8154d097d226

React/Base/Surface/RCTSurfaceRootShadowView.m

@@ -46,7 +46,6 @@ - (void)layoutWithAffectedShadowViews:(NSHashTable<RCTShadowView *> *)affectedSh
   NSHashTable<NSString *> *other = [NSHashTable new];
 
   RCTLayoutContext layoutContext = {};
-  layoutContext.absolutePosition = CGPointZero;
   layoutContext.affectedShadowViews = affectedShadowViews;
   layoutContext.other = other;
 

ReactCommon/fabric/components/text/paragraph/ParagraphShadowNode.cpp

@@ -206,7 +206,6 @@ void ParagraphShadowNode::layout(LayoutContext layoutContext) {
     auto attachmentOrigin = roundToPixel<&round>(
         attachmentFrame.origin, layoutMetrics.pointScaleFactor);
     auto attachmentLayoutContext = layoutContext;
-    attachmentLayoutContext.absolutePosition += attachmentOrigin;
     auto attachmentLayoutConstrains = LayoutConstraints{
         attachmentSize, attachmentSize, layoutConstraints.layoutDirection};
 

ReactCommon/fabric/core/layout/LayoutContext.h

@@ -20,11 +20,6 @@ namespace react {
  * layout approaches.
  */
 struct LayoutContext {
-  /*
-   * Compound absolute position of the node relative to the root node.
-   */
-  Point absolutePosition{0, 0};
-
   /*
    * Reflects the scale factor needed to convert from the logical coordinate
    * space into the device coordinate space of the physical screen.

ReactCommon/fabric/core/layout/LayoutableShadowNode.cpp

@@ -219,9 +219,6 @@ void LayoutableShadowNode::layout(LayoutContext layoutContext) {
       continue;
     }
 
-    auto childLayoutContext = LayoutContext(layoutContext);
-    childLayoutContext.absolutePosition += childLayoutMetrics.frame.origin;
-
     child->layout(layoutContext);
   }
 }