base: Add three helper functions to Values API.

chrome/test/webdriver/web_element_id.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/test/webdriver/web_element_id.h"
 
 #include "base/logging.h"
 #include "base/values.h"
 
 namespace {
@@ skipping 25 matching lines @@
     is_valid_ = static_cast<DictionaryValue*>(value)->
         GetString(kWebElementKey, &id_);
   }
 }
 
 WebElementId::~WebElementId() {}
 
 Value* WebElementId::ToValue() const {
   CHECK(is_valid_);
   if (id_.empty())
-    return Value::CreateNullValue();
+    return base::NullValue();
   DictionaryValue* element = new DictionaryValue();
   element->SetString(kWebElementKey, id_);
   return element;
 }
 
 bool WebElementId::is_valid() const {
   return is_valid_;
 }
 
 }  // namespace webdriver