Convert UserPolicySigninService to use OAuth2TokenService

chrome/browser/policy/cloud/user_policy_signin_service_base.cc

Index: chrome/browser/policy/cloud/user_policy_signin_service_base.cc
diff --git a/chrome/browser/policy/cloud/user_policy_signin_service_base.cc b/chrome/browser/policy/cloud/user_policy_signin_service_base.cc
index d50902ec6c83f497fd86330fd241741ae53bfb1c..ae1d7bdfa080f684d0479f21f1537f69412f363e 100644
--- a/chrome/browser/policy/cloud/user_policy_signin_service_base.cc
+++ b/chrome/browser/policy/cloud/user_policy_signin_service_base.cc
@@ -133,6 +133,10 @@ void UserPolicySigninServiceBase::OnClientError(CloudPolicyClient* client) {
 }
 
 void UserPolicySigninServiceBase::Shutdown() {
+  PrepareForUserCloudPolicyManagerShutdown();
+}
+
+void UserPolicySigninServiceBase::PrepareForUserCloudPolicyManagerShutdown() {
   UserCloudPolicyManager* manager = GetManager();
   if (manager && manager->core()->client())
     manager->core()->client()->RemoveObserver(this);
@@ -230,7 +234,7 @@ void UserPolicySigninServiceBase::InitializeUserCloudPolicyManager(
 }
 
 void UserPolicySigninServiceBase::ShutdownUserCloudPolicyManager() {
-  Shutdown();
+  PrepareForUserCloudPolicyManagerShutdown();
   UserCloudPolicyManager* manager = GetManager();
   if (manager)
     manager->DisconnectAndRemovePolicy();