Refactor the client certificate code in chromeos/network/.

chromeos/network/network_connection_handler.h

Index: chromeos/network/network_connection_handler.h
diff --git a/chromeos/network/network_connection_handler.h b/chromeos/network/network_connection_handler.h
index 1dfca49f69efa56fec29a916c7227e0a602e2e49..46b5ff3ee34bae4e7cc221063a1baa99522d92b4 100644
--- a/chromeos/network/network_connection_handler.h
+++ b/chromeos/network/network_connection_handler.h
@@ -164,7 +164,10 @@ class CHROMEOS_EXPORT NetworkConnectionHandler
 
   void CheckPendingRequest(const std::string service_path);
   void CheckAllPendingRequests();
-  bool CertificateIsConfigured(NetworkUIData* ui_data, std::string* pkcs11_id);
+
+  // Returns the PKCS#11 ID of a cert matching the certificate pattern in
+  // |ui_data|. Returns empty string otherwise.
+  std::string CertificateIsConfigured(NetworkUIData* ui_data);
   void ErrorCallbackForPendingRequest(const std::string& service_path,
                                       const std::string& error_name);