Convert UserPolicySigninService to use OAuth2TokenService

components/browser_context_keyed_service/browser_context_keyed_base_factory.cc

Index: components/browser_context_keyed_service/browser_context_keyed_base_factory.cc
diff --git a/components/browser_context_keyed_service/browser_context_keyed_base_factory.cc b/components/browser_context_keyed_service/browser_context_keyed_base_factory.cc
index e6caa69d63c9792a3ec7ccf74b0975ab24c1d6c1..cc3f487d1886cc75300ab36e0dec6afba8cb5715 100644
--- a/components/browser_context_keyed_service/browser_context_keyed_base_factory.cc
+++ b/components/browser_context_keyed_service/browser_context_keyed_base_factory.cc
@@ -68,7 +68,6 @@ void BrowserContextKeyedBaseFactory::RegisterUserPrefsOnBrowserContext(
   // to enforce a uniquenes check here because some tests create one context and
   // multiple services of the same type attached to that context (serially, not
   // parallel) and we don't want to register multiple times on the same context.
-  DCHECK(!context->IsOffTheRecord());
 
   std::set<content::BrowserContext*>::iterator it =
       registered_preferences_.find(context);