Add AddCallbackForCookie method to CookieStore.

net/cookies/canonical_cookie.cc

 // Copyright (c) 2012 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.
 
 // Portions of this code based on Mozilla:
 //   (netwerk/cookie/src/nsCookieService.cpp)
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
@@ skipping 376 matching lines @@
 
 std::string CanonicalCookie::DebugString() const {
   return base::StringPrintf(
       "name: %s value: %s domain: %s path: %s creation: %"
       PRId64,
       name_.c_str(), value_.c_str(),
       domain_.c_str(), path_.c_str(),
       static_cast<int64>(creation_date_.ToTimeT()));
 }
 
-CanonicalCookie* CanonicalCookie::Duplicate() {
+CanonicalCookie* CanonicalCookie::Duplicate() const {
   CanonicalCookie* cc = new CanonicalCookie();
   cc->source_ = source_;
   cc->name_ = name_;
   cc->value_ = value_;
   cc->domain_ = domain_;
   cc->path_ = path_;
   cc->creation_date_ = creation_date_;
   cc->expiry_date_ = expiry_date_;
   cc->last_access_date_ = last_access_date_;
   cc->secure_ = secure_;
   cc->httponly_ = httponly_;
   cc->priority_ = priority_;
   return cc;
 }
 
 }  // namespace net