Fabric: Proxying `LayoutConstraints::direction` down to RootNode's styles

Summary:
Trivial.
We have to proxy layout directions as well as min and max sizes to RootNode's Props to properly communicate the constrains to Yoga.

Reviewed By: sahrens

Differential Revision: D10387798

fbshipit-source-id: a02ec0a20b3ef28f6230738e5b3a4a2b0b8e0961

ReactCommon/fabric/components/root/RootProps.cpp

@@ -26,6 +26,9 @@ static YGStyle yogaStyleFromLayoutConstraints(
   yogaStyle.maxDimensions[YGDimensionHeight] =
       yogaStyleValueFromFloat(layoutConstraints.maximumSize.height);
 
+  yogaStyle.direction =
+      yogaDirectionFromLayoutDirection(layoutConstraints.layoutDirection);
+
   return yogaStyle;
 }
 

ReactCommon/fabric/components/view/conversions.h

@@ -113,6 +113,17 @@ inline LayoutMetrics layoutMetricsFromYogaNode(YGNode &yogaNode) {
   return layoutMetrics;
 }
 
+inline YGDirection yogaDirectionFromLayoutDirection(LayoutDirection direction) {
+  switch (direction) {
+    case LayoutDirection::Undefined:
+      return YGDirectionInherit;
+    case LayoutDirection::LeftToRight:
+      return YGDirectionLTR;
+    case LayoutDirection::RightToLeft:
+      return YGDirectionRTL;
+  }
+}
+
 inline void fromDynamic(const folly::dynamic &value, YGDirection &result) {
   assert(value.isString());
   auto stringValue = value.asString();

ReactCommon/fabric/core/layout/LayoutConstraints.h

@@ -19,7 +19,7 @@ namespace react {
 struct LayoutConstraints {
   Size minimumSize{0, 0};
   Size maximumSize{kFloatUndefined, kFloatUndefined};
-  LayoutDirection layoutDirection;
+  LayoutDirection layoutDirection{LayoutDirection::Undefined};
 };
 
 } // namespace react