Unify object groups iteration in global handles.

src/global-handles.h

Index: src/global-handles.h
diff --git a/src/global-handles.h b/src/global-handles.h
index 482baef3fa4b62a0c05be194a94163967a4e18cb..6cb141d2659ebaa966e0435e68bc909be4094c04 100644
--- a/src/global-handles.h
+++ b/src/global-handles.h
@@ -206,6 +206,11 @@ class GlobalHandles {
   // See the note above.
   void IterateNewSpaceWeakIndependentRoots(ObjectVisitor* v);
 
+  // Iterate over objects in object groups that have at least one object
+  // which requires visiting. The callback has to return true if objects
+  // can be skipped and false otherwise.
+  bool IterateObjectGroups(ObjectVisitor* v, WeakSlotCallbackWithHeap f);
+
   // Add an object group.
   // Should be only used in GC callback function before a collection.
   // All groups are destroyed after a garbage collection.