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

ui/ozone/platform/dri/native_display_delegate_dri.cc

Index: ui/ozone/platform/dri/native_display_delegate_dri.cc
diff --git a/ui/ozone/platform/dri/native_display_delegate_dri.cc b/ui/ozone/platform/dri/native_display_delegate_dri.cc
index b242283a88b8b8d0e420d9a1c0b0fa1199c37556..a5776f4781e3545e80aeab27509fc64c81c0544c 100644
--- a/ui/ozone/platform/dri/native_display_delegate_dri.cc
+++ b/ui/ozone/platform/dri/native_display_delegate_dri.cc
@@ -226,6 +226,12 @@ void NativeDisplayDelegateDri::AddGraphicsDevice(
 
   scoped_refptr<DriWrapper> device =
       drm_device_generator_->CreateDevice(path, file.Pass());
+  if (!device) {
+    LOG(WARNING) << "Could not initialize DRM device for '" << path.value()

[alexst (slow to review), 2015/02/23 21:46:32]

Would this log every time there is a vgem device?

[dnicoara, 2015/02/23 21:49:10]

Yes.

+                 << "'";
+    return;
+  }
+
   devices_.push_back(device);
   if (io_task_runner_)
     device->InitializeTaskRunner(io_task_runner_);