Correct const accessors in base/values.(h|cc)

chrome/test/webdriver/commands/title_command.h

 // 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.
 
 #ifndef CHROME_TEST_WEBDRIVER_COMMANDS_TITLE_COMMAND_H_
 #define CHROME_TEST_WEBDRIVER_COMMANDS_TITLE_COMMAND_H_
 
 #include <string>
 #include <vector>
 
 #include "chrome/test/webdriver/commands/webdriver_command.h"
 
 namespace webdriver {
 
 class Response;
 
 // A call with HTTP GET will return the title of the tab. See:
 // http://code.google.com/p/selenium/wiki/JsonWireProtocol#/session/:sessionId/title
 class TitleCommand : public WebDriverCommand {
  public:
   TitleCommand(const std::vector<std::string>& path_segments,
-               const DictionaryValue* const parameters);
+               DictionaryValue* const parameters);
   virtual ~TitleCommand();
 
   virtual bool DoesGet() OVERRIDE;
   virtual void ExecuteGet(Response* const response) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TitleCommand);
 };
 
 }  // namespace webdriver
 
 #endif  // CHROME_TEST_WEBDRIVER_COMMANDS_TITLE_COMMAND_H_