Media Galleries API: Fix MediaGalleriesPreferences finders race.

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

Index: chrome/browser/ui/webui/options/media_galleries_handler.cc
diff --git a/chrome/browser/ui/webui/options/media_galleries_handler.cc b/chrome/browser/ui/webui/options/media_galleries_handler.cc
index 982aaeb2aa5c9a0f0b4f5e0278f870a58431c884..0a676f6a6fb25541a8a4d2f7701bc85c320a6292 100644
--- a/chrome/browser/ui/webui/options/media_galleries_handler.cc
+++ b/chrome/browser/ui/webui/options/media_galleries_handler.cc
@@ -47,12 +47,15 @@ void MediaGalleriesHandler::GetLocalizedValues(DictionaryValue* values) {
 }
 
 void MediaGalleriesHandler::InitializePage() {
-  StorageMonitor::GetInstance()->EnsureInitialized(
-      base::Bind(&MediaGalleriesHandler::InitializeOnStorageMonitorInit,
-                 weak_ptr_factory_.GetWeakPtr()));
+  Profile* profile = Profile::FromWebUI(web_ui());
+  MediaGalleriesPreferences* preferences =
+      g_browser_process->media_file_system_registry()->GetPreferences(profile);
+  preferences->EnsureInitialized(base::Bind(
+      &MediaGalleriesHandler::InitializeOnMediaGalleriesPreferencesInit,
+      weak_ptr_factory_.GetWeakPtr()));
 }
 
-void MediaGalleriesHandler::InitializeOnStorageMonitorInit() {
+void MediaGalleriesHandler::InitializeOnMediaGalleriesPreferencesInit() {
   Profile* profile = Profile::FromWebUI(web_ui());
   if (!MediaGalleriesPreferences::APIHasBeenUsed(profile))
     return;
@@ -90,6 +93,7 @@ void MediaGalleriesHandler::OnGalleriesChanged() {
   Profile* profile = Profile::FromWebUI(web_ui());
   MediaGalleriesPreferences* preferences =
       g_browser_process->media_file_system_registry()->GetPreferences(profile);
+  DCHECK(preferences->IsInitialized());
 
   ListValue list;
   const MediaGalleriesPrefInfoMap& galleries = preferences->known_galleries();
@@ -138,6 +142,7 @@ void MediaGalleriesHandler::HandleForgetGallery(const base::ListValue* args) {
   MediaGalleriesPreferences* preferences =
       g_browser_process->media_file_system_registry()->GetPreferences(
           Profile::FromWebUI(web_ui()));
+  DCHECK(preferences->IsInitialized());
   preferences->ForgetGalleryById(id);
 }
 
@@ -148,6 +153,7 @@ void MediaGalleriesHandler::FileSelected(const base::FilePath& path,
   MediaGalleriesPreferences* preferences =
       g_browser_process->media_file_system_registry()->GetPreferences(
           Profile::FromWebUI(web_ui()));
+  DCHECK(preferences->IsInitialized());
   preferences->AddGalleryByPath(path);
 }