[Offline Pages] Two-step expiration in storage manager.

components/offline_pages/offline_page_client_policy.h

 // Copyright 2016 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 COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_CLIENT_POLICY_H_
 #define COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_CLIENT_POLICY_H_
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/time/time.h"
 
 namespace offline_pages {
 
-static const int kUnlimitedPages = 0;
+static const size_t kUnlimitedPages = 0;
 
 // The struct describing the lifetime policy of offline pages.
 // The following behaviors are controlled by policy:
 //    a. Persistency of the offline page.
 //    b. Expiration time of an offline page
 //    c. Limit of number of pages offline.
 struct LifetimePolicy {
   // Type of the client, indicating where the archived page would be saved
   // and whether it could be kept indefinitely.
   enum class LifetimeType {
     TEMPORARY,
     PERSISTENT,
   };
 
   // Type of the page generated by the client.
   LifetimeType lifetime_type;
 
   // The time after which the page expires.
   base::TimeDelta expiration_period;
 
   // The maximum number of pages allowed to be saved by the namespace.
   // kUnlimitedPages (defined above) means no limit set.
-  int page_limit;
+  size_t page_limit;
 };
 
 // The struct describing policies for various namespaces (Bookmark, Last-N etc.)
 // used by offline page model. The name_space is supposed to be key, so that
 // it's sufficient to compare name_space only when doing comparisons.
 struct OfflinePageClientPolicy {
   // Namespace to which the policy applied.
   std::string name_space;
 
   // Policy to control the lifetime of a page generated by this namespace.
   LifetimePolicy lifetime_policy;
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_CLIENT_POLICY_H_