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 d9d15d8eb120492768543020067dc906564a6136..b0f3ad173c1ed5250a25518b906347fd7949abf2 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -109,6 +109,7 @@
 
 #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)
@@ -564,6 +565,7 @@ 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);