[Offline Pages] Linking storage manager and model with UMAs.

components/offline_pages/offline_page_model.h

 // Copyright 2015 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_MODEL_H_
 #define COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_MODEL_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 322 matching lines @@
   // Similar to DoDeletePagesByOfflineId, does actual work of deleting, and
   // requires that the model is loaded.
   void DoDeletePagesByURLPredicate(const UrlPredicate& predicate,
                                    const DeletePageCallback& callback);
 
   // Callback completing page expiration.
   void OnExpirePageDone(int64_t offline_id,
                         const base::Time& expiration_time,
                         bool success);
 
+  // Calls storage manager to clear expired pages if there's any. Used to

[jianli, 2016/05/27 19:16:13]

nit: you don't need to explain the implementation details in the function
comment. Probably just enough to say:
  // Clears expired pages if there are any.

[romax, 2016/05/27 20:36:02]

Done.

+  // invoke ClearPagesIfNeeded on storage manager to clear storage
+  // 'automatically'.
+  void ClearStorageIfNeeded(
+      const OfflinePageStorageManager::ClearStorageCallback& callback);
+
+  // Callback completing storage clearing/

[jianli, 2016/05/27 19:16:13]

nit: / => .

[romax, 2016/05/27 20:36:02]

Done.

+  void OnStorageCleared(const size_t expired_page_count,
+                        OfflinePageStorageManager::ClearStorageResult result);
+
   void RunWhenLoaded(const base::Closure& job);
 
   // Persistent store for offline page metadata.
   std::unique_ptr<OfflinePageMetadataStore> store_;
 
   // Location where all of the archive files will be stored.
   base::FilePath archives_dir_;
 
   // The observers.
   base::ObserverList<Observer> observers_;
@@ skipping 20 matching lines @@
   std::unique_ptr<ArchiveManager> archive_manager_;
 
   base::WeakPtrFactory<OfflinePageModel> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(OfflinePageModel);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_MODEL_H_