Enable weak embedded objects in optimized code with a fix for heap verifier.

src/objects.h

 // Copyright 2012 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 3983 matching lines @@
   }
 
   // Looks up the value associated with the given key. The hole value is
   // returned in case the key is not present.
   Object* Lookup(Object* key);
 
   // Adds (or overwrites) the value associated with the given key. Mapping a
   // key to the hole value causes removal of the whole entry.
   MUST_USE_RESULT MaybeObject* Put(Object* key, Object* value);
 
+  // This function is called when heap verification is turned on.
+  void Zap(Object* value) {
+    int capacity = Capacity();
+    for (int i = 0; i < capacity; i++) {
+      set(EntryToIndex(i), value);
+      set(EntryToValueIndex(i), value);
+    }
+  }
+
  private:
   friend class MarkCompactCollector;
 
   void AddEntry(int entry, Object* key, Object* value);
 
   // Returns the index to the value of an entry.
   static inline int EntryToValueIndex(int entry) {
     return EntryToIndex(entry) + 1;
   }
 };
@@ skipping 6271 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_