Don't crash on device resolution failure.

chrome/browser/local_discovery/privet_notifications.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/local_discovery/privet_notifications.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
@@ skipping 99 matching lines @@
             description.address,
             base::Bind(&PrivetNotificationsListener::CreateInfoOperation,
                        base::Unretained(this)));
 
     device_context->privet_http_resolution->Start();
   }
 }
 
 void PrivetNotificationsListener::CreateInfoOperation(
     scoped_ptr<PrivetHTTPClient> http_client) {
+  if (!http_client) {
+    // Do nothing if resolution fails.
+    return;
+  }
+
   std::string name = http_client->GetName();
   DeviceContextMap::iterator device_iter = devices_seen_.find(name);
   DCHECK(device_iter != devices_seen_.end());
   DeviceContext* device = device_iter->second.get();
   device->privet_http.swap(http_client);
   device->info_operation = device->privet_http->CreateInfoOperation(
       base::Bind(&PrivetNotificationsListener::OnPrivetInfoDone,
                  base::Unretained(this),
                  device));
   device->info_operation->Start();
@@ skipping 272 matching lines @@
 
 void PrivetNotificationDelegate::DisableNotifications() {
   Profile* profile_obj = Profile::FromBrowserContext(profile_);
 
   profile_obj->GetPrefs()->SetBoolean(
       prefs::kLocalDiscoveryNotificationsEnabled,
       false);
 }
 
 }  // namespace local_discovery