add baseline start and baseline end events

Summary: Adds Baseline start and end events to be handled later for instrumentation

Reviewed By: davidaurelio

Differential Revision: D16048790

fbshipit-source-id: 8409dbb633168753a7bf8fab20bc6551d113ddd6

tests/EventsTest.cpp

@@ -300,6 +300,9 @@ void EventTest::listen(const YGNode& node, Event::Type type, Event::Data data) {
     case Event::MeasureCallbackStart:
     case Event::MeasureCallbackEnd:
       break;
+    case Event::NodeBaselineStart:
+    case Event::NodeBaselineEnd:
+      break;
   }
 }
 

yoga/Yoga.cpp

@@ -997,12 +997,18 @@ static inline YGAlign YGNodeAlignItem(const YGNode* node, const YGNode* child) {
 
 static float YGBaseline(const YGNodeRef node, void* layoutContext) {
   if (node->hasBaselineFunc()) {
+
+    Event::publish<Event::NodeBaselineStart>(node);
+
     const float baseline = marker::MarkerSection<YGMarkerBaselineFn>::wrap(
         node,
         &YGNode::baseline,
         node->getLayout().measuredDimensions[YGDimensionWidth],
         node->getLayout().measuredDimensions[YGDimensionHeight],
         layoutContext);
+
+    Event::publish<Event::NodeBaselineEnd>(node);
+
     YGAssertWithNode(
         node,
         !YGFloatIsUndefined(baseline),

yoga/event/event.h

@@ -33,6 +33,8 @@ struct Event {
     LayoutPassEnd,
     MeasureCallbackStart,
     MeasureCallbackEnd,
+    NodeBaselineStart,
+    NodeBaselineEnd,
   };
   class Data;
   using Subscriber = void(const YGNode&, Type, Data);