[Sync] Log age of auth tokens on authentication failure

chrome/browser/signin/about_signin_internals_factory.cc

Index: chrome/browser/signin/about_signin_internals_factory.cc
diff --git a/chrome/browser/signin/about_signin_internals_factory.cc b/chrome/browser/signin/about_signin_internals_factory.cc
index 21a0922241253d8ea534f175816dd308c4126319..d3abc380872c9a8918768456445b5e64777aa5cf 100644
--- a/chrome/browser/signin/about_signin_internals_factory.cc
+++ b/chrome/browser/signin/about_signin_internals_factory.cc
@@ -62,12 +62,15 @@ void AboutSigninInternalsFactory::RegisterUserPrefs(
     const std::string value = pref + ".value";
     const std::string status = pref + ".status";
     const std::string time = pref + ".time";
+    const std::string time_internal = pref + ".time_internal";
     user_prefs->RegisterStringPref(
         value.c_str(), std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
     user_prefs->RegisterStringPref(
         status.c_str(), std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
     user_prefs->RegisterStringPref(
         time.c_str(), std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
+    user_prefs->RegisterInt64Pref(
+        time_internal.c_str(), 0, PrefRegistrySyncable::UNSYNCABLE_PREF);
   }
 }