[Media Galleries] Lazily initialize the storage monitor.

chrome/browser/extensions/api/media_galleries_private/gallery_watch_state_tracker.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.
 
 // GalleryWatchStateTracker tracks the gallery watchers, updates the
 // extension state storage and observes the notification events.
 // GalleryWatchStateTracker lives on the UI thread.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_MEDIA_GALLERIES_PRIVATE_GALLERY_WATCH_STATE_TRACKER_H_
 #define CHROME_BROWSER_EXTENSIONS_API_MEDIA_GALLERIES_PRIVATE_GALLERY_WATCH_STATE_TRACKER_H_
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/media_galleries/media_galleries_preferences.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class Profile;
 
 namespace base {
 class Value;
 }
 
+namespace chrome {
+class MediaGalleriesPreferences;
+}
+
 namespace extensions {
 
 class GalleryWatchStateTracker
     : public content::NotificationObserver,
       public base::SupportsWeakPtr<GalleryWatchStateTracker> {
  public:
   explicit GalleryWatchStateTracker(Profile* profile);
   virtual ~GalleryWatchStateTracker();
 
   // Returns the GalleryWatchStateTracker associated with the |profile|.
@@ skipping 21 matching lines @@
 
   // Returns a set of watched gallery identifiers for the extension specified
   // by the |extension_id|.
   chrome::MediaGalleryPrefIdSet GetAllWatchedGalleryIDsForExtension(
       const std::string& extension_id) const;
 
   // Removes all the gallery watchers associated with the extension specified
   // by the |extension_id|.
   void RemoveAllGalleryWatchersForExtension(const std::string& extension_id);
 
+  // Once we learn the preferences, set them in the tracker.
+  void SetPreferences(chrome::MediaGalleriesPreferences* preferences);
+
  private:
   // Key: Gallery identifier.
   // Value: True if the watcher is active. Watcher will be active only if
   // the extension has access permission to the watched gallery and a watcher
   // has been successfully setup.
   typedef std::map<chrome::MediaGalleryPrefId, bool> WatchedGalleriesMap;
 
   // Key: Extension identifier.
   // Value: Map of watched gallery information.
   typedef std::map<std::string, WatchedGalleriesMap> WatchedExtensionsMap;
 
   // content::NotificationObserver implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   // Syncs media gallery watch data for the given extension to/from the state
   // storage.
   void WriteToStorage(const std::string& extension_id);
   void ReadFromStorage(const std::string& extension_id,
                        scoped_ptr<base::Value> value);
+  void ReadFromStorageWithPreferences(
+      const std::string& extension_id,
+      chrome::MediaGalleryPrefIdSet gallery_ids,
+      chrome::MediaGalleriesPreferences* preferences);
 
   // Sets up the gallery watcher on the receipt of granted gallery permission
   // event.
   void SetupGalleryWatch(const std::string& extension_id,
                          chrome::MediaGalleryPrefId gallery_id);
 
   // Removes the gallery watcher on the receipt of revoked gallery permission
   // event.
   void RemoveGalleryWatch(const std::string& extension_id,
                           chrome::MediaGalleryPrefId gallery_id);
@@ skipping 15 matching lines @@
   // extension specified by the |extension_id|. Returns true if the |gallery_id|
   // is added into the |watched_extensions_map_| and returns false if the
   // |gallery_id| already exists in the |watched_extensions_map_|.
   bool AddWatchedGalleryIdInfoForExtension(
       const std::string& extension_id,
       chrome::MediaGalleryPrefId gallery_id);
 
   // Current profile.
   Profile* profile_;
 
+  // The preferences object from which we get gallery information.

[vandebo (ex-Chrome), 2013/05/16 18:56:27]

I assume the lifetime of this class is such that we don't have to worry about
storing a raw pointer?  If so, please add a comment to that effect.

[Greg Billock, 2013/05/16 23:27:55]

Both are effectively profile scoped, but there may be shutdown issues we need to
control for.

+  chrome::MediaGalleriesPreferences* preferences_;
+
   // Used to listen for NOTIFICATION_EXTENSION_LOADED and
   // NOTIFICATION_EXTENSION_UNLOADED events.
   content::NotificationRegistrar registrar_;
 
   // A map of watched gallery details, per extension.
   WatchedExtensionsMap watched_extensions_map_;
 
   DISALLOW_COPY_AND_ASSIGN(GalleryWatchStateTracker);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_MEDIA_GALLERIES_PRIVATE_GALLERY_WATCH_STATE_TRACKER_H_