Moved isLeadingPos defined as a method on YGNode

Summary: Moved isLeadingPos defined as a method on YGNode

Reviewed By: emilsjolander

Differential Revision: D6682956

fbshipit-source-id: 31c60e0eae906e1434a6969f3cd786fcaf9097a5

yoga/YGNode.cpp

@@ -102,6 +102,14 @@ float YGNode::getLeadingPosition(
       : YGResolveValue(*leadingPosition, axisSize);
 }
 
+bool YGNode::isLeadingPositionDefined(const YGFlexDirection axis) {
+  return (YGFlexDirectionIsRow(axis) &&
+          YGComputedEdgeValue(style_.position, YGEdgeStart, &YGValueUndefined)
+                  ->unit != YGUnitUndefined) ||
+      YGComputedEdgeValue(style_.position, leading[axis], &YGValueUndefined)
+          ->unit != YGUnitUndefined;
+}
+
 // Setters
 
 void YGNode::setContext(void* context) {