Fix cloud policy duplicate registrations issue.

chrome/browser/policy/cloud_policy_client.cc

Index: chrome/browser/policy/cloud_policy_client.cc
diff --git a/chrome/browser/policy/cloud_policy_client.cc b/chrome/browser/policy/cloud_policy_client.cc
index 51f8ae3c8e09a6452e18ec6a6a73f501c62fc717..a7b08716b026d8b9c3a5deabc57a03e076c81958 100644
--- a/chrome/browser/policy/cloud_policy_client.cc
+++ b/chrome/browser/policy/cloud_policy_client.cc
@@ -110,6 +110,9 @@ void CloudPolicyClient::Register(em::DeviceRegisterRequest::Type type,
   if (is_auto_enrollement)
     request->set_auto_enrolled(true);
 
+  request_job_->SetRetryCallback(
+      base::Bind(&CloudPolicyClient::OnRetryRegister, base::Unretained(this)));
+
   request_job_->Start(base::Bind(&CloudPolicyClient::OnRegisterCompleted,
                                  base::Unretained(this)));
 }
@@ -207,6 +210,16 @@ const em::PolicyFetchResponse* CloudPolicyClient::GetPolicyFor(
   return it == responses_.end() ? NULL : it->second;
 }
 
+void CloudPolicyClient::OnRetryRegister(DeviceManagementRequestJob* job) {
+  DCHECK_EQ(request_job_.get(), job);
+  // If the initial request managed to get to the server but the response didn't
+  // arrive at the client then retrying with the same client ID will fail.
+  // Set the re-registration flag so that the server accepts it.
+  // If the server hasn't seen the client ID before then it will also accept
+  // the re-registration.
+  job->GetRequest()->mutable_register_request()->set_reregister(true);
+}
+
 void CloudPolicyClient::OnRegisterCompleted(
     DeviceManagementStatus status,
     const em::DeviceManagementResponse& response) {