[Offline Pages] Updated clearing logic 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 51 matching lines @@
                          const StorageStatsCallback& callback) {
   ArchiveManager::StorageStats storage_stats;
   storage_stats.free_disk_space =
       base::SysInfo::AmountOfFreeDiskSpace(archive_dir);
   storage_stats.total_archives_size = base::ComputeDirectorySize(archive_dir);
   task_runner->PostTask(FROM_HERE, base::Bind(callback, storage_stats));
 }
 
 }  // namespace
 
+// protected and used for testing.
+ArchiveManager::ArchiveManager() {}
+
 ArchiveManager::ArchiveManager(
     const base::FilePath& archives_dir,
     const scoped_refptr<base::SequencedTaskRunner>& task_runner)
     : archives_dir_(archives_dir), task_runner_(task_runner) {}
 
 ArchiveManager::~ArchiveManager() {}
 
 void ArchiveManager::EnsureArchivesDirCreated(const base::Closure& callback) {
   task_runner_->PostTaskAndReply(
       FROM_HERE, base::Bind(EnsureArchivesDirCreatedImpl, archives_dir_),
@@ skipping 30 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