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

chrome/test/webdriver/commands/source_command.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/commands/source_command.h"
 
 #include <string>
 
 #include "base/values.h"
 #include "chrome/test/webdriver/commands/response.h"
 #include "chrome/test/webdriver/webdriver_error.h"
 #include "chrome/test/webdriver/webdriver_session.h"
 
 namespace webdriver {
 
 // Private atom to find source code of the page.
 const char* const kSource =
     "return new XMLSerializer().serializeToString(document);";
 
 SourceCommand::SourceCommand(const std::vector<std::string>& path_segments,
-                             const DictionaryValue* const parameters)
+                             DictionaryValue* const parameters)
     : WebDriverCommand(path_segments, parameters) {}
 
 SourceCommand::~SourceCommand() {}
 
 bool SourceCommand::DoesGet() {
   return true;
 }
 
 void SourceCommand::ExecuteGet(Response* const response) {
   ListValue args;
   Value* result = NULL;
   Error* error = session_->ExecuteScript(kSource, &args, &result);
   if (error) {
     response->SetError(error);
     return;
   }
   response->SetValue(result);
 }
 
 }  // namespace webdriver