Introduce ProcessYoungWeakReferences and process weak list of allocation sites just during full GCs.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 147d5ddff02578e3fa82428f3672fac83a900712..c76f691f0d22369501cb5b177bd7519097126b04 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -1597,7 +1597,7 @@ void Heap::Scavenge() {
   incremental_marking()->UpdateMarkingDequeAfterScavenge();
 
   ScavengeWeakObjectRetainer weak_object_retainer(this);
-  ProcessWeakReferences(&weak_object_retainer);
+  ProcessYoungWeakReferences(&weak_object_retainer);
 
   DCHECK(new_space_front == new_space_.top());
 
@@ -1684,11 +1684,9 @@ void Heap::UpdateReferencesInExternalStringTable(
 }
 
 
-void Heap::ProcessWeakReferences(WeakObjectRetainer* retainer) {
+void Heap::ProcessAllWeakReferences(WeakObjectRetainer* retainer) {
   ProcessArrayBuffers(retainer);
   ProcessNativeContexts(retainer);
-  // TODO(mvstanton): AllocationSites only need to be processed during
-  // MARK_COMPACT, as they live in old space. Verify and address.
   ProcessAllocationSites(retainer);
   // Collects callback info for handles that are pending (about to be
   // collected) and either phantom or internal-fields.  Releases the global
@@ -1697,6 +1695,16 @@ void Heap::ProcessWeakReferences(WeakObjectRetainer* retainer) {
 }
 
 
+void Heap::ProcessYoungWeakReferences(WeakObjectRetainer* retainer) {
+  ProcessArrayBuffers(retainer);
+  ProcessNativeContexts(retainer);
+  // Collects callback info for handles that are pending (about to be
+  // collected) and either phantom or internal-fields.  Releases the global
+  // handles.  See also PostGarbageCollectionProcessing.
+  isolate()->global_handles()->CollectPhantomCallbackData();
+}
+
+
 void Heap::ProcessNativeContexts(WeakObjectRetainer* retainer) {
   Object* head = VisitWeakList<Context>(this, native_contexts_list(), retainer);
   // Update the head of the list of contexts.