[Media Galleries] Lazily initialize the storage monitor.

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

Index: chrome/browser/extensions/api/media_galleries_private/media_galleries_private_api.h
diff --git a/chrome/browser/extensions/api/media_galleries_private/media_galleries_private_api.h b/chrome/browser/extensions/api/media_galleries_private/media_galleries_private_api.h
index af0e1ea8707defe8459735fddaf9918714abd059..894afb47861a9779ea80a21fc2afaf524439d234 100644
--- a/chrome/browser/extensions/api/media_galleries_private/media_galleries_private_api.h
+++ b/chrome/browser/extensions/api/media_galleries_private/media_galleries_private_api.h
@@ -108,6 +108,9 @@ class MediaGalleriesPrivateAddGalleryWatchFunction
   virtual bool RunImpl() OVERRIDE;
 
  private:
+  void OnPreferences(chrome::MediaGalleryPrefId pref_id,
+                     chrome::MediaGalleriesPreferences* preferences);
+
   // Gallery watch request handler.
   void HandleResponse(chrome::MediaGalleryPrefId gallery_id,
                       bool success);
@@ -151,6 +154,11 @@ class MediaGalleriesPrivateRemoveAllGalleryWatchFunction
 
   // SyncExtensionFunction overrides.
   virtual bool RunImpl() OVERRIDE;
+
+ private:
+  void OnPreferences(
+      chrome::MediaGalleriesPreferences* preferences,
+      chrome::MediaGalleryPrefId pref_id);
 };
 
 // Implements the chrome.mediaGalleriesPrivate.ejectDevice method.