base: Add three helper functions to Values API.

chrome/test/webdriver/commands/set_timeout_commands_unittest.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 <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 #include "chrome/test/webdriver/commands/set_timeout_commands.h"
@@ skipping 50 matching lines @@
   path_segments.push_back("timeouts");
   path_segments.push_back("implicitly_wait");
 
   DictionaryValue* parameters = new DictionaryValue;  // Owned by |command|.
   ImplicitWaitCommand command(path_segments, parameters);
 
   AssertIsAbleToInitialize(&command);
 
   AssertError(kBadRequest, "Request missing ms parameter", &command);
 
-  parameters->Set("ms", Value::CreateNullValue());
+  parameters->Set("ms", base::NullValue());
   AssertError(kBadRequest, "ms parameter is not a number", &command);
 
   parameters->SetString("ms", "apples");
   AssertError(kBadRequest, "ms parameter is not a number", &command);
 
   parameters->SetInteger("ms", -1);
   AssertError(kBadRequest, "timeout must be non-negative: -1", &command);
 
   parameters->SetDouble("ms", -3.0);
   AssertError(kBadRequest, "timeout must be non-negative: -3", &command);
 
   parameters->SetInteger("ms", 1);
   AssertTimeoutSet(test_session, 1, &command);
   parameters->SetDouble("ms", 2.5);
   AssertTimeoutSet(test_session, 2, &command);
   parameters->SetInteger("ms", 0);
   AssertTimeoutSet(test_session, 0, &command);
 }
 
 }  // namespace webdriver