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

chrome/test/webdriver/commands/execute_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_EXECUTE_COMMAND_H_
 #define CHROME_TEST_WEBDRIVER_COMMANDS_EXECUTE_COMMAND_H_
 
 #include <string>
 #include <vector>
 
 #include "chrome/test/webdriver/commands/webdriver_command.h"
 
 namespace webdriver {
 
 class Response;
 
 // Inject a snippet of javascript into the page and return its result.
 // WebElements that should be passed to the script as an argument should be
 // specified in the arguments array as WebElement JSON arguments. Likewise,
 // any WebElements in the script result will be returned to the client as
 // WebElement JSON objects. See:
 // http://code.google.com/p/selenium/wiki/JsonWireProtocol#/session/:sessionId/execute
 class ExecuteCommand : public WebDriverCommand {
  public:
   ExecuteCommand(const std::vector<std::string>& path_segments,
-                 const DictionaryValue* const parameters);
+                 DictionaryValue* const parameters);
   virtual ~ExecuteCommand();
 
   virtual bool DoesPost() OVERRIDE;
   virtual void ExecutePost(Response* const response) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ExecuteCommand);
 };
 
 }  // namespace webdriver
 
 #endif  // CHROME_TEST_WEBDRIVER_COMMANDS_EXECUTE_COMMAND_H_