Fix chromium-style compile error that got in the tree since yesterday.

chrome/test/webdriver/cookie.h

 // Copyright (c) 2010 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_COOKIE_H_
 #define CHROME_TEST_WEBDRIVER_COOKIE_H_
 #pragma once
 
 #include <string>
 
 #include "base/values.h"
 
 namespace webdriver {
 
 // Class used to convert cookies to various formats.
 class Cookie {
  public:
   explicit Cookie(const std::string& cookie);
   explicit Cookie(const DictionaryValue& dict);
+  ~Cookie();
 
   DictionaryValue* ToDictionary();
   // ToJSONString() returns a string form of a JSON object with the required
   // WebDriver tags.  Note that this format cannot be used to set a cookie in
   // the chrome browser.  Example { "name"="foo", "value"="bar"}
   std::string ToJSONString();
   // ToString() returns a string format expected by chrome to for a cookie.
   // Example: "foo=bar"
   std::string ToString();
 
   bool valid() const { return valid_; }
   const std::string& name() const { return name_; }
 
  private:
   std::string name_;
   std::string value_;
   std::string path_;
   std::string domain_;
   std::string expires_;
   bool secure_;
   bool http_;
   bool valid_;
 
   DISALLOW_COPY_AND_ASSIGN(Cookie);
 };
 
 }  // namespace webdriver
 
 #endif  // CHROME_TEST_WEBDRIVER_COOKIE_H_