Expose dirtied func in Javascript bindings (#842)

Summary:
Yoga currently has the concept of a 'dirtied func', which is called when a Node becomes dirty, which can be useful to trigger a repaint. This PR exposes that functionality in the Javascript bindings.
Pull Request resolved: https://github.com/facebook/yoga/pull/842

Reviewed By: SidharthGuglani

Differential Revision: D13847093

Pulled By: davidaurelio

fbshipit-source-id: 41913abd6eedc46ee7d66929140e08a084f23972

javascript/sources/Node.hh

@@ -161,6 +161,15 @@ class Node {
 
     Size callMeasureFunc(double width, int widthMode, double height, int heightMode) const;
 
+ public: // Dirtied func mutators
+
+   void setDirtiedFunc(nbind::cbFunction & dirtiedFunc);
+   void unsetDirtiedFunc(void);
+
+ public: // Dirtied func inspectors
+
+    void callDirtiedFunc(void) const;
+
  public: // Dirtiness accessors
 
     void markDirty(void);
@@ -194,5 +203,5 @@ class Node {
     YGNodeRef m_node;
 
     std::unique_ptr<nbind::cbFunction> m_measureFunc;
-
+    std::unique_ptr<nbind::cbFunction> m_dirtiedFunc;
 };