Implement local storage for App List in case app sync is off.

chrome/browser/prefs/browser_prefs.cc

Index: chrome/browser/prefs/browser_prefs.cc
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 641844a72279bd3a6b232a6593f10ec0d7db93ff..715d5ec631be55ec8232c00534fc39d7ce06c727 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -110,6 +110,7 @@
 
 #if BUILDFLAG(ENABLE_APP_LIST)
 #include "chrome/browser/apps/drive/drive_app_mapping.h"
+#include "chrome/browser/ui/app_list/app_list_syncable_service.h"
 #endif
 
 #if BUILDFLAG(ENABLE_BACKGROUND)
@@ -566,6 +567,7 @@ void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry) {
   DevToolsWindow::RegisterProfilePrefs(registry);
 #if BUILDFLAG(ENABLE_APP_LIST)
   DriveAppMapping::RegisterProfilePrefs(registry);
+  app_list::AppListSyncableService::RegisterProfilePrefs(registry);
 #endif
   extensions::CommandService::RegisterProfilePrefs(registry);
   extensions::ExtensionSettingsHandler::RegisterProfilePrefs(registry);