Implement mediaGalleriesPrivate api to notify extensions about gallery changed events.

chrome/browser/extensions/api/media_galleries_private/gallery_watch_manager.h

+// Copyright (c) 2012 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.
+
+// Manages all the gallery file watchers for the associated profile. This
+// is temporary and will be moved to a permanent, public place in the near
+// future.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_MEDIA_GALLERIES_PRIVATE_GALLERY_WATCH_MANAGER_H_
+#define CHROME_BROWSER_EXTENSIONS_API_MEDIA_GALLERIES_PRIVATE_GALLERY_WATCH_MANAGER_H_
+
+#include <map>
+#include <string>
+
+#include "base/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "base/time.h"
+
+class Profile;
+
+namespace extensions {
+
+class GalleryFilePathWatcher;
+
+// The profile-keyed service that manages the gallery watchers. This class

[Lei Zhang, 2012/12/18 01:45:16]

profile-keyed services inherit from ProfileKeyedService.

[kmadhusu, 2012/12/18 21:32:39]

Removed the class header comments and added a couple of lines in file header
comments.

+// lives on the FILE thread.
+class GalleryWatchManager {
+ public:
+  // Returns the GalleryWatchManager for |profile|, creating it if it is not
+  // yet created.
+  static GalleryWatchManager* GetForProfile(const Profile* profile);
+
+  // Returns true if an GalleryWatchManager already exists for the specified
+  // |profile|.
+  static bool HasForProfile(const Profile* profile);
+
+  // Notifies about the |profile| shutdown event.
+  static void OnProfileShutdown(const Profile* profile);
+
+  ~GalleryWatchManager();
+
+  // Initiates a gallery watch operation for the extension specified by
+  // the |extension_id|. |gallery_id| specifies the gallery identifier and
+  // |watch_path| specifies the absolute path of the gallery. Returns true,
+  // if the watch was set successfully.
+  bool StartGalleryWatch(const std::string& gallery_id,
+                         const FilePath& watch_path,
+                         const std::string& extension_id);
+
+  // Cancels the gallery watch operation for the extension specified by the
+  // |extension_id|. |watch_path| specifies the gallery absolute path.
+  void StopGalleryWatch(const FilePath& watch_path,
+                        const std::string& extension_id);
+
+  // Handles the extension unloaded/uninstalled/destroyed event.
+  void OnExtensionDestroyed(const std::string& extension_id);

[Lei Zhang, 2012/12/18 00:47:01]

If you also make this a static function like OnProfileShutdown(), then you won't
need HandleExtensionDestroyedOnFileThread().

[kmadhusu, 2012/12/18 21:32:39]

OnProfileShutdown() implementation modifies the global variable where as
OnExtensionDestroyed() modifies the non-static class member variable. Therefore,
it cannot be a static function of this class.

+
+ private:
+  typedef std::map<FilePath, scoped_refptr<GalleryFilePathWatcher> > WatcherMap;
+
+  // Use GetForProfile().
+  explicit GalleryWatchManager(const Profile* profile);
+
+  // Deletes the gallery watchers.
+  void DeleteAllWatchers();
+
+  // Current profile.
+  const Profile* profile_;
+
+  // Map to manage the gallery file path watchers.
+  // Key: Gallery watch path.
+  // Value: GalleryFilePathWatcher*.
+  WatcherMap gallery_watchers_;
+
+  DISALLOW_COPY_AND_ASSIGN(GalleryWatchManager);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_MEDIA_GALLERIES_PRIVATE_GALLERY_WATCH_MANAGER_H_