Reland: Reland: Implement new Blink IDL attribute [SetReference]

Source/bindings/v8/DOMWrapperMap.h

 /*
  * Copyright (C) 2012 Google Inc. 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
@@ skipping 45 matching lines @@
 
     bool setReturnValueFrom(v8::ReturnValue<v8::Value> returnValue, KeyType* key)
     {
         typename MapType::iterator it = m_map.find(key);
         if (it == m_map.end())
             return false;
         returnValue.Set(*(it->value.persistent()));
         return true;
     }
 
+    void setReferenceFrom(const v8::Persistent<v8::Object>& parent, KeyType* key, v8::Isolate* isolate)
+    {
+        m_map.get(key).setReferenceFrom(parent, isolate);

[haraken, 2013/10/17 00:47:31]

It looks OK to use UnsafePersistent in DOMWrapperMap. Shall we use an
UnsafePersistent here and remove UnsafePersistent::setReferenceFrom?

Also, shall we rename the method to setReference"To" ? This is a method used for
[ReachableTo].

[kouhei (in TOK), 2013/10/17 02:30:09]

Discussed offline.

This is also called from DOMWrapperMap. I think it is better not to expose
persistent() anymore.

+    }
+
     bool containsKey(KeyType* key)
     {
         return m_map.find(key) != m_map.end();
     }
 
     bool containsKeyAndValue(KeyType* key, const v8::Persistent<v8::Object>& value)
     {
         typename MapType::iterator it = m_map.find(key);
         if (it == m_map.end())
             return false;
@@ skipping 49 matching lines @@
     ASSERT(type->derefObjectFunction);
     void* key = static_cast<void*>(toNative(*wrapper));
     ASSERT(*(map->m_map.get(key).persistent()) == *wrapper);
     map->removeAndDispose(key);
     type->derefObject(key);
 }
 
 } // namespace WebCore
 
 #endif // DOMWrapperMap_h