Implement prologue weak persistent handles.

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index fbf78b31a8ccc8182e104cfc1010c0f3397484b8..26124f7130340713ac18ee11ed8b4afaa3f868b6 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -423,6 +423,7 @@ RawError* Isolate::StandardRunLoop() {
 
 
 void Isolate::VisitObjectPointers(ObjectPointerVisitor* visitor,
+                                  bool visit_prologue_weak_handles,
                                   bool validate_frames) {
   ASSERT(visitor != NULL);
 
@@ -445,7 +446,7 @@ void Isolate::VisitObjectPointers(ObjectPointerVisitor* visitor,
 
   // Visit the dart api state for all local and persistent handles.
   if (api_state() != NULL) {
-    api_state()->VisitObjectPointers(visitor);
+    api_state()->VisitObjectPointers(visitor, visit_prologue_weak_handles);
   }
 
   // Visit all objects in the code index table.
@@ -461,9 +462,10 @@ void Isolate::VisitObjectPointers(ObjectPointerVisitor* visitor,
 }
 
 
-void Isolate::VisitWeakPersistentHandles(HandleVisitor* visitor) {
+void Isolate::VisitWeakPersistentHandles(HandleVisitor* visitor,
+                                         bool visit_prologue_weak_handles) {
   if (api_state() != NULL) {
-    api_state()->VisitWeakHandles(visitor);
+    api_state()->VisitWeakHandles(visitor, visit_prologue_weak_handles);
   }
 }