Fix a crash in LocalDiscoveryUIHandler.

chrome/browser/ui/webui/local_discovery/local_discovery_ui_handler.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/webui/local_discovery/local_discovery_ui_handler.h"
 
 #include <set>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 586 matching lines @@
         base::UTF8ToUTF16(email));
   }
   base::StringValue label(label_str);
 
   web_ui()->CallJavascriptFunction(
       "local_discovery.setupCloudPrintConnectorSection", disabled, label,
       allowed);
 }
 
 void LocalDiscoveryUIHandler::RefreshCloudPrintStatusFromService() {
-  GetCloudPrintProxyService()->RefreshStatusFromService();
+  auto* service = GetCloudPrintProxyService();
+  if (service)
+    service->RefreshStatusFromService();
 }
 
 CloudPrintProxyService* LocalDiscoveryUIHandler::GetCloudPrintProxyService() {
   return CloudPrintProxyServiceFactory::GetForProfile(
       Profile::FromWebUI(web_ui()));
 }
 #endif  // defined(CLOUD_PRINT_CONNECTOR_UI_AVAILABLE)
 
 }  // namespace local_discovery