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

ui/ozone/platform/dri/native_display_delegate_dri.cc

 // Copyright 2014 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/native_display_delegate_dri.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_descriptor_posix.h"
 #include "base/files/file.h"
@@ skipping 201 matching lines @@
   return true;
 }
 
 void NativeDisplayDelegateDri::AddGraphicsDevice(
     const base::FilePath& path,
     const base::FileDescriptor& fd) {
   base::File file(fd.fd);
   auto it =
       std::find_if(devices_.begin(), devices_.end(), FindByDevicePath(path));
   if (it != devices_.end()) {
-    LOG(WARNING) << "Got request to add existing device '" << path.value()
-                 << "'";
+    VLOG(2) << "Got request to add existing device '" << path.value() << "'";
     return;
   }
 
   scoped_refptr<DriWrapper> device =
       drm_device_generator_->CreateDevice(path, file.Pass());
+  if (!device) {
+    VLOG(2) << "Could not initialize DRM device for '" << path.value() << "'";
+    return;
+  }
+
   devices_.push_back(device);
   if (io_task_runner_)
     device->InitializeTaskRunner(io_task_runner_);
 }
 
 void NativeDisplayDelegateDri::RemoveGraphicsDevice(
     const base::FilePath& path) {
   auto it =
       std::find_if(devices_.begin(), devices_.end(), FindByDevicePath(path));
   if (it == devices_.end()) {
-    LOG(ERROR) << "Got request to remove non-existent device '" << path.value()
-               << "'";
+    VLOG(2) << "Got request to remove non-existent device '" << path.value()
+            << "'";
     return;
   }
 
   devices_.erase(it);
 }
 
 DisplaySnapshotDri* NativeDisplayDelegateDri::FindDisplaySnapshot(int64_t id) {
   for (size_t i = 0; i < cached_displays_.size(); ++i)
     if (cached_displays_[i]->display_id() == id)
       return cached_displays_[i];
@@ skipping 157 matching lines @@
 
     if (it == old_displays.end()) {
       screen_manager_->AddDisplayController(new_displays[i]->drm(),
                                             new_displays[i]->crtc(),
                                             new_displays[i]->connector());
     }
   }
 }
 
 }  // namespace ui