[DICE] Enable sync for an account that is already present in the token service.

chrome/browser/policy/cloud/user_policy_signin_service.cc

Index: chrome/browser/policy/cloud/user_policy_signin_service.cc
diff --git a/chrome/browser/policy/cloud/user_policy_signin_service.cc b/chrome/browser/policy/cloud/user_policy_signin_service.cc
index 0a5e82188b4a3c268627c61b99829b82ba3b4a79..e7b0d2eca88393cced4ef4f8c795be2050caea0a 100644
--- a/chrome/browser/policy/cloud/user_policy_signin_service.cc
+++ b/chrome/browser/policy/cloud/user_policy_signin_service.cc
@@ -71,7 +71,7 @@ void UserPolicySigninService::Shutdown() {
   oauth2_token_service_->RemoveObserver(this);
 }
 
-void UserPolicySigninService::RegisterForPolicy(
+void UserPolicySigninService::RegisterForPolicyWithLoginToken(
     const std::string& username,
     const std::string& oauth2_refresh_token,
     const PolicyRegistrationCallback& callback) {
@@ -101,6 +101,35 @@ void UserPolicySigninService::RegisterForPolicy(
                  callback));
 }
 
+void UserPolicySigninService::RegisterForPolicyWithAccountId(
+    const std::string& username,
+    const std::string& account_id,
+    const PolicyRegistrationCallback& callback) {
+  DCHECK(!account_id.empty());
+
+  // Create a new CloudPolicyClient for fetching the DMToken.
+  std::unique_ptr<CloudPolicyClient> policy_client =
+      CreateClientForRegistrationOnly(username);
+  if (!policy_client) {
+    callback.Run(std::string(), std::string());
+    return;
+  }
+
+  // Fire off the registration process. Callback keeps the CloudPolicyClient
+  // alive for the length of the registration process. Use the system
+  // request context because the user is not signed in to this profile yet
+  // (we are just doing a test registration to see if policy is supported for
+  // this user).
+  registration_helper_.reset(new CloudPolicyClientRegistrationHelper(

[pastarmovj, 2017/07/05 13:56:21]

nit: Modernize this and the function above to base::MakeUnique call if possible.

[msarda, 2017/07/05 15:53:59]

Done.

+      policy_client.get(),
+      enterprise_management::DeviceRegisterRequest::BROWSER));
+  registration_helper_->StartRegistration(
+      oauth2_token_service_, account_id,
+      base::Bind(&UserPolicySigninService::CallPolicyRegistrationCallback,
+                 base::Unretained(this), base::Passed(&policy_client),
+                 callback));
+}
+
 void UserPolicySigninService::CallPolicyRegistrationCallback(
     std::unique_ptr<CloudPolicyClient> client,
     PolicyRegistrationCallback callback) {