arc: Register media files to MediaProvider.

chrome/browser/chromeos/arc/arc_downloads_watcher_service.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 CHROME_BROWSER_CHROMEOS_ARC_ARC_DOWNLOADS_WATCHER_SERVICE_H_
+#define CHROME_BROWSER_CHROMEOS_ARC_ARC_DOWNLOADS_WATCHER_SERVICE_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "components/arc/arc_bridge_service.h"
+#include "components/arc/arc_service.h"
+
+namespace base {
+
+class FilePath;
+
+}  // namespace base
+
+namespace arc {
+
+// Watches Downloads directory and registers newly created media files to
+// Android MediaProvider.
+class ArcDownloadsWatcherService : public ArcService,
+                                   public ArcBridgeService::Observer {
+ public:
+  explicit ArcDownloadsWatcherService(ArcBridgeService* bridge_service);
+  ~ArcDownloadsWatcherService() override;
+
+  // ArcBridgeService::Observer
+  void OnFileSystemInstanceReady() override;
+  void OnFileSystemInstanceClosed() override;
+
+ private:
+  class DownloadsWatcher;
+
+  void StartWatchDownloads();

[Luis Héctor Chávez, 2016/05/20 15:18:59]

nit: StartWatchingDownloads() or StartDownloadsWatch(). Same below.

[Shuhei Takahashi, 2016/05/24 08:46:34]

Done.

+  void StopWatchDownloads();
+
+  void OnDownloadsChanged(const std::vector<base::FilePath>& paths);
+
+  std::unique_ptr<DownloadsWatcher> watcher_;
+
+  // Note: This should remain the last member so it'll be destroyed and
+  // invalidate the weak pointers before any other members are destroyed.
+  base::WeakPtrFactory<ArcDownloadsWatcherService> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ArcDownloadsWatcherService);
+};
+
+}  // namespace arc
+
+#endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_DOWNLOADS_WATCHER_SERVICE_H_