add UserProxyService to get username

src/main/java/com/google/webauthn/gaedemo/servlets/RemoveCredential.java

@@ -14,8 +14,10 @@
 
 package com.google.webauthn.gaedemo.servlets;
 
+import com.google.appengine.api.users.User;
 import com.google.appengine.api.users.UserService;
 import com.google.appengine.api.users.UserServiceFactory;
+import com.google.webauthn.gaedemo.service.UserProxyService;
 import com.google.webauthn.gaedemo.storage.Credential;
 import java.io.IOException;
 import java.util.List;
@@ -42,7 +44,14 @@ public class RemoveCredential extends HttpServlet {
   @Override
   protected void doGet(HttpServletRequest request, HttpServletResponse response)
       throws ServletException, IOException {
+    /* Tyler start -----------------*/
+    UserProxyService userProxyService = UserProxyService.getInstance();
+    User user = userProxyService.getCurrentUser();
+    String currentUser = (user != null) ? user.getEmail() : userService.getCurrentUser().getEmail();
+    /* Tyler end -----------------*/
+    /* Original code
     String currentUser = userService.getCurrentUser().getEmail();
+     */
     Credential.remove(currentUser, request.getParameter("id"));