Attempt to collect more garbage before panicking with out of memory.

src/global-handles.h

 // Copyright 2007-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 77 matching lines @@
 
   // Clear the weakness of a global handle.
   static void ClearWeakness(Object** location);
 
   // Tells whether global handle is near death.
   static bool IsNearDeath(Object** location);
 
   // Tells whether global handle is weak.
   static bool IsWeak(Object** location);
 
-  // Process pending weak handles.
-  static void PostGarbageCollectionProcessing();
+  // Process pending weak handles.  Returns true if any weak handle
+  // callback has been invoked.
+  static bool PostGarbageCollectionProcessing();
 
   // Iterates over all strong handles.
   static void IterateStrongRoots(ObjectVisitor* v);
 
   // Iterates over all handles.
   static void IterateAllRoots(ObjectVisitor* v);
 
   // Iterates over all weak roots in heap.
   static void IterateWeakRoots(ObjectVisitor* v);
 
@@ skipping 61 matching lines @@
   static Node* first_deallocated() { return first_deallocated_; }
   static void set_first_deallocated(Node* value) {
     first_deallocated_ = value;
   }
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBAL_HANDLES_H_