Create TetherService, a TetherAllowed pref, and use DependencyManager for RegisterProfilePrefs call…

chrome/browser/signin/easy_unlock_service_factory.cc

Index: chrome/browser/signin/easy_unlock_service_factory.cc
diff --git a/chrome/browser/signin/easy_unlock_service_factory.cc b/chrome/browser/signin/easy_unlock_service_factory.cc
index 998648ba7508b8a7f500261c00d2891cdf278f4a..9c68aed27545ffefbd962f14cc652d726267c133 100644
--- a/chrome/browser/signin/easy_unlock_service_factory.cc
+++ b/chrome/browser/signin/easy_unlock_service_factory.cc
@@ -16,6 +16,7 @@
 #include "chrome/common/chrome_switches.h"
 #include "chrome/grit/browser_resources.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "components/pref_registry/pref_registry_syncable.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/extension_system_provider.h"
 #include "extensions/browser/extensions_browser_client.h"
@@ -108,6 +109,13 @@ KeyedService* EasyUnlockServiceFactory::BuildServiceInstanceFor(
   return service;
 }
 
+void EasyUnlockServiceFactory::RegisterProfilePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+#if BUILDFLAG(ENABLE_EXTENSIONS)
+  EasyUnlockService::RegisterProfilePrefs(registry);
+#endif
+}
+
 content::BrowserContext* EasyUnlockServiceFactory::GetBrowserContextToUse(
       content::BrowserContext* context) const {
 #if defined(OS_CHROMEOS)