Allow SetHiddenValue to accept empty value.

src/api.cc

 // 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 3281 matching lines @@
   i::HandleScope scope(isolate);
   i::Handle<i::JSObject> self = Utils::OpenHandle(this);
   return i::JSObject::GetIdentityHash(self);
 }
 
 
 bool v8::Object::SetHiddenValue(v8::Handle<v8::String> key,
                                 v8::Handle<v8::Value> value) {
   i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
   ON_BAILOUT(isolate, "v8::Object::SetHiddenValue()", return false);
+  if (value.IsEmpty()) return DeleteHiddenValue(key);
   ENTER_V8(isolate);
   i::HandleScope scope(isolate);
   i::Handle<i::JSObject> self = Utils::OpenHandle(this);
   i::Handle<i::String> key_obj = Utils::OpenHandle(*key);
   i::Handle<i::String> key_symbol = FACTORY->LookupSymbol(key_obj);
   i::Handle<i::Object> value_obj = Utils::OpenHandle(*value);
   i::Handle<i::Object> result =
       i::JSObject::SetHiddenProperty(self, key_symbol, value_obj);
   return *result == *self;
 }
@@ skipping 3208 matching lines @@
 
   v->VisitPointers(blocks_.first(), first_block_limit_);
 
   for (int i = 1; i < blocks_.length(); i++) {
     v->VisitPointers(blocks_[i], &blocks_[i][kHandleBlockSize]);
   }
 }
 
 
 } }  // namespace v8::internal