[Media Gallery] Add existing attached devices to the prefs in time for media galleries dialog.

chrome/browser/media_gallery/media_file_system_registry.h

Index: chrome/browser/media_gallery/media_file_system_registry.h
diff --git a/chrome/browser/media_gallery/media_file_system_registry.h b/chrome/browser/media_gallery/media_file_system_registry.h
index 45f3163d0b4e665e26968a21e35dfe9015718a92..84bc3155fdf99b3a55e35894f21a16682f34a7f2 100644
--- a/chrome/browser/media_gallery/media_file_system_registry.h
+++ b/chrome/browser/media_gallery/media_file_system_registry.h
@@ -90,6 +90,13 @@ class MediaFileSystemRegistry
       const extensions::Extension* extension,
       const MediaFileSystemsCallback& callback);
 
+  // Returns the initialized media galleries preferences for the specified
+  // |profile|. This method should be used instead of calling
+  // MediaGalleriesPreferences directly because this method also ensures that
+  // currently attached removable devices are added to the preferences.
+  // Called on the UI thread.
+  MediaGalleriesPreferences* GetPreferences(Profile* profile);
+
   // base::SystemMonitor::DevicesChangedObserver implementation.
   virtual void OnRemovableStorageAttached(
       const std::string& id, const string16& name,
@@ -129,10 +136,6 @@ class MediaFileSystemRegistry
       const FilePath::StringType& device_location);
 #endif
 
-  // Register all the media devices found in system monitor as auto-detected
-  // galleries for the passed |preferences|.
-  void AddAttachedMediaDeviceGalleries(MediaGalleriesPreferences* preferences);
-
   void OnExtensionGalleriesHostEmpty(Profile* profile,
                                      const std::string& extension_id);