Mirror app list hierarchy data in profile prefs.

chrome/browser/ui/app_list/app_list_syncable_service.cc

Index: chrome/browser/ui/app_list/app_list_syncable_service.cc
diff --git a/chrome/browser/ui/app_list/app_list_syncable_service.cc b/chrome/browser/ui/app_list/app_list_syncable_service.cc
index f4d38d99435653204034badc8b1bda7df44e83f4..c5a7857b29f8a8d7423f392f46111fdf55fcad78 100644
--- a/chrome/browser/ui/app_list/app_list_syncable_service.cc
+++ b/chrome/browser/ui/app_list/app_list_syncable_service.cc
@@ -9,9 +9,11 @@
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/app_list/app_list_prefs.h"
 #include "chrome/browser/ui/app_list/app_list_service.h"
 #include "chrome/browser/ui/app_list/extension_app_item.h"
 #include "chrome/browser/ui/app_list/extension_app_model_builder.h"
+#include "chrome/browser/ui/app_list/model_pref_updater.h"
 #include "chrome/browser/ui/host_desktop.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_constants.h"
@@ -264,6 +266,9 @@ void AppListSyncableService::BuildModel() {
     apps_builder_->InitializeWithProfile(profile_, model_.get());
   }
 
+  model_pref_updater_.reset(
+      new ModelPrefUpdater(AppListPrefs::Get(profile_), model_.get()));
+
   if (app_list::switches::IsDriveAppsInAppListEnabled())
     drive_app_provider_.reset(new DriveAppProvider(profile_));
 }