Node -> Measure func map instead of vec (#1581)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1581

This is better than just trusting the order of the measure func call. Now each measure function I/O is associated with a node in the JSON.

Reviewed By: NickGerleman

Differential Revision: D53776790

fbshipit-source-id: 793cf2d9cbf6f663d24848af0af30aa297614eea

benchmark/TreeDeserialization.h

@@ -18,11 +18,6 @@ namespace facebook::yoga {
 
 using namespace nlohmann;
 
-struct MeasureFuncVecWithIndex {
-  std::vector<SerializedMeasureFunc> vec;
-  size_t index;
-};
-
 YGFlexDirection flexDirectionFromString(std::string str);
 
 YGJustify justifyContentFromString(std::string str);
@@ -53,7 +48,5 @@ YGDirection directionFromString(std::string str);
 
 YGMeasureMode measureModeFromString(std::string str);
 
-void populateMeasureFuncVec(
-    json& j,
-    std::shared_ptr<MeasureFuncVecWithIndex> fns);
+SerializedMeasureFunc serializedMeasureFuncFromJson(json& j);
 } // namespace facebook::yoga