[Media Galleries] Lazily initialize the storage monitor.

chrome/browser/ui/webui/options/media_galleries_handler.h

Index: chrome/browser/ui/webui/options/media_galleries_handler.h
diff --git a/chrome/browser/ui/webui/options/media_galleries_handler.h b/chrome/browser/ui/webui/options/media_galleries_handler.h
index 441e7364ffafdd3507c013b7a3d72d0f6dfe0970..8e4471046d3f6281207529f01365932358dae955 100644
--- a/chrome/browser/ui/webui/options/media_galleries_handler.h
+++ b/chrome/browser/ui/webui/options/media_galleries_handler.h
@@ -6,7 +6,9 @@
 #define CHROME_BROWSER_UI_WEBUI_OPTIONS_MEDIA_GALLERIES_HANDLER_H_
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_change_registrar.h"
+#include "chrome/browser/media_galleries/media_galleries_preferences.h"
 #include "chrome/browser/ui/webui/options/options_ui.h"
 #include "content/public/browser/notification_observer.h"
 #include "ui/shell_dialogs/select_file_dialog.h"
@@ -40,10 +42,16 @@ class MediaGalleriesHandler : public OptionsPageUIHandler,
   // Called when the list of known galleries has changed; updates the page.
   void OnGalleriesChanged();
 
+  // Bottom half of |OnGalleriesChanged| after async call to initialize
+  // StorageMonitor.
+  void OnStorageMonitorInitialized();
+
   PrefChangeRegistrar pref_change_registrar_;
 
   scoped_refptr<ui::SelectFileDialog> select_file_dialog_;
 
+  base::WeakPtrFactory<MediaGalleriesHandler> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(MediaGalleriesHandler);
 };