[Ozone-Dri] Gracefully handle DRM devices with no resources

ui/ozone/platform/dri/drm_device_generator.cc

 // Copyright 2015 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 "ui/ozone/platform/dri/drm_device_generator.h"
 
 #include "ui/ozone/platform/dri/dri_wrapper.h"
 
 namespace ui {
 
 DrmDeviceGenerator::DrmDeviceGenerator() {
 }
 
 DrmDeviceGenerator::~DrmDeviceGenerator() {
 }
 
 scoped_refptr<DriWrapper> DrmDeviceGenerator::CreateDevice(
     const base::FilePath& device_path,
     base::File file) {
   scoped_refptr<DriWrapper> drm = new DriWrapper(device_path, file.Pass());
-  drm->Initialize();
-  return drm;
+  if (drm->Initialize())
+    return drm;
+
+  return nullptr;
 }
 
 }  // namespace ui