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

net/base/static_cookie_policy.cc

 // 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.
 
 #include "net/base/static_cookie_policy.h"
 
 #include "base/logging.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/net_errors.h"
 #include "net/base/registry_controlled_domain.h"
 
 namespace net {
 
 int StaticCookiePolicy::CanGetCookies(const GURL& url,
                                       const GURL& first_party_for_cookies,
                                       CompletionCallback* callback) {
   switch (type_) {
     case StaticCookiePolicy::ALLOW_ALL_COOKIES:
+    case StaticCookiePolicy::BLOCK_SETTING_THIRD_PARTY_COOKIES:
       return OK;
-    case StaticCookiePolicy::BLOCK_THIRD_PARTY_COOKIES:
-      return OK;
+    case StaticCookiePolicy::BLOCK_ALL_THIRD_PARTY_COOKIES:
+      if (first_party_for_cookies.is_empty())
+        return OK;  // Empty first-party URL indicates a first-party request.
+      return RegistryControlledDomainService::SameDomainOrHost(
+          url, first_party_for_cookies) ? OK : ERR_ACCESS_DENIED;
     case StaticCookiePolicy::BLOCK_ALL_COOKIES:
       return ERR_ACCESS_DENIED;
     default:
       NOTREACHED();
       return ERR_ACCESS_DENIED;
   }
 }
 
 int StaticCookiePolicy::CanSetCookie(const GURL& url,
                                      const GURL& first_party_for_cookies,
                                      const std::string& cookie_line,
                                      CompletionCallback* callback) {
   switch (type_) {
     case StaticCookiePolicy::ALLOW_ALL_COOKIES:
       return OK;
-    case StaticCookiePolicy::BLOCK_THIRD_PARTY_COOKIES:
+    case StaticCookiePolicy::BLOCK_SETTING_THIRD_PARTY_COOKIES:
+    case StaticCookiePolicy::BLOCK_ALL_THIRD_PARTY_COOKIES:
       if (first_party_for_cookies.is_empty())
         return OK;  // Empty first-party URL indicates a first-party request.
       return RegistryControlledDomainService::SameDomainOrHost(
           url, first_party_for_cookies) ? OK : ERR_ACCESS_DENIED;
     case StaticCookiePolicy::BLOCK_ALL_COOKIES:
       return ERR_ACCESS_DENIED;
     default:
       NOTREACHED();
       return ERR_ACCESS_DENIED;
   }
 }
 
 }  // namespace net