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

components/offline_pages/archive_manager.cc

 // 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.
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 22 matching lines @@
 }
 
 void DeleteArchivesImpl(const std::vector<base::FilePath>& file_paths,
                         scoped_refptr<base::SequencedTaskRunner> task_runner,
                         const base::Callback<void(bool)>& callback) {
   bool result = false;
   for (const auto& file_path : file_paths) {
     // Make sure delete happens on the left of || so that it is always executed.
     result = base::DeleteFile(file_path, false) || result;
   }
+  if (file_paths.size() == 0)
+    result = true;
   task_runner->PostTask(FROM_HERE, base::Bind(callback, result));
 }
 
 void GetAllArchivesImpl(
     const base::FilePath& archive_dir,
     scoped_refptr<base::SequencedTaskRunner> task_runner,
     const base::Callback<void(const std::set<base::FilePath>&)>& callback) {
   std::set<base::FilePath> archive_paths;
   base::FileEnumerator file_enumerator(archive_dir, false,
                                        base::FileEnumerator::FILES);
@@ skipping 62 matching lines @@
 }
 
 void ArchiveManager::GetStorageStats(
     const StorageStatsCallback& callback) const {
   task_runner_->PostTask(
       FROM_HERE, base::Bind(GetStorageStatsImpl, archives_dir_,
                             base::ThreadTaskRunnerHandle::Get(), callback));
 }
 
 }  // namespace offline_pages