Collect phantom callback data only once during gc. For scavenges, just consider the young handles r…

src/global-handles.h

Index: src/global-handles.h
diff --git a/src/global-handles.h b/src/global-handles.h
index 20da53a185c4a232864c71c4bbbb6e2a2306d2bd..767989c77e3ceb23f6602294e2c0e27da2421e0a 100644
--- a/src/global-handles.h
+++ b/src/global-handles.h
@@ -165,7 +165,11 @@ class GlobalHandles {
 
   // Collect up data for the weak handle callbacks after GC has completed, but
   // before memory is reclaimed.
-  void CollectPhantomCallbackData();
+  void CollectAllPhantomCallbackData();
+
+  // Collect up data for the weak handle callbacks referenced by young
+  // generation after GC has completed, but before memory is reclaimed.
+  void CollectYoungPhantomCallbackData();
 
   // Clear the weakness of a global handle.
   static void* ClearWeakness(Object** location);