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

chrome/test/webdriver/commands/create_session.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_CREATE_SESSION_H_
 #define CHROME_TEST_WEBDRIVER_COMMANDS_CREATE_SESSION_H_
 
 #include <string>
 #include <vector>
 
 #include "chrome/test/webdriver/commands/command.h"
 
 namespace webdriver {
 
 class Response;
 
 // Create a new session which is a new instance of the chrome browser with no
 // page loaded.  A new session ID is passed back to the user which is used for
 // all future commands that are sent to control this new instance.  The
 // desired capabilities should be specified in a JSON object with the
 // following properties:
 // http://code.google.com/p/selenium/wiki/JsonWireProtocol#/session
 class CreateSession : public Command {
  public:
   CreateSession(const std::vector<std::string>& path_segments,
-                const DictionaryValue* const parameters);
+                DictionaryValue* const parameters);
   virtual ~CreateSession();
 
   virtual bool DoesPost() OVERRIDE;
   virtual void ExecutePost(Response* const response) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CreateSession);
 };
 
 }  // namespace webdriver
 
 #endif  // CHROME_TEST_WEBDRIVER_COMMANDS_CREATE_SESSION_H_