Clarify wording around blocking 3rd party cookies and add lab to block reading of 3rd party cookies

chrome/browser/net/chrome_cookie_policy.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_BROWSER_NET_CHROME_COOKIE_POLICY_H_
 #define CHROME_BROWSER_NET_CHROME_COOKIE_POLICY_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 10 matching lines @@
 // We will only prompt the user before setting a cookie.  We do not prompt the
 // user before getting a cookie.  However, if we are in the process of
 // prompting the user, then any requests to get cookies will be deferred.
 // This is done so that cookie requests remain FIFO.
 //
 class ChromeCookiePolicy
     : public base::RefCountedThreadSafe<ChromeCookiePolicy>,
       public net::CookiePolicy {
  public:
   explicit ChromeCookiePolicy(HostContentSettingsMap* map);
-  ~ChromeCookiePolicy();
+  virtual ~ChromeCookiePolicy();
 
   // CookiePolicy methods:
   virtual int CanGetCookies(const GURL& url, const GURL& first_party,
                             net::CompletionCallback* callback);
   virtual int CanSetCookie(const GURL& url, const GURL& first_party,
                            const std::string& cookie_line,
                            net::CompletionCallback* callback);
 
  private:
   class Completion {
@@ skipping 21 matching lines @@
   typedef std::vector<Completion> Completions;
   typedef std::map<std::string, Completions> HostCompletionsMap;
 
   int CheckPolicy(const GURL& url) const;
 
   // A map from hostname to callbacks awaiting a cookie policy response.
   // This map is only accessed on the IO thread.
   HostCompletionsMap host_completions_map_;
 
   scoped_refptr<HostContentSettingsMap> host_content_settings_map_;
+
+  // True if blocking third-party cookies also applies to reading them.
+  bool strict_third_party_blocking_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeCookiePolicy);
 };
 
 #endif  // CHROME_BROWSER_NET_CHROME_COOKIE_POLICY_H_