Figure out the default graphics card on the Browser process

ui/ozone/platform/dri/native_display_delegate_proxy.h

 // 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.
 
 #ifndef UI_OZONE_PLATFORM_DRI_NATIVE_DISPLAY_DELEGATE_PROXY_H_
 #define UI_OZONE_PLATFORM_DRI_NATIVE_DISPLAY_DELEGATE_PROXY_H_
 
 #include <map>
 
 #include "base/files/file.h"
+#include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/observer_list.h"
 #include "ui/display/types/native_display_delegate.h"
 #include "ui/events/ozone/device/device_event_observer.h"
 #include "ui/ozone/public/gpu_platform_support_host.h"
 
 namespace ui {
 
 class DeviceManager;
 class DisplayManager;
 class DriGpuPlatformSupportHost;
 
 struct DisplaySnapshot_Params;
 
 class NativeDisplayDelegateProxy : public NativeDisplayDelegate,
                                    public DeviceEventObserver,
                                    public GpuPlatformSupportHost {
  public:
   NativeDisplayDelegateProxy(DriGpuPlatformSupportHost* proxy,
                              DeviceManager* device_manager,
-                             DisplayManager* display_manager);
+                             DisplayManager* display_manager,
+                             const base::FilePath& primary_graphics_card_path);
   ~NativeDisplayDelegateProxy() override;
 
   // NativeDisplayDelegate overrides:
   void Initialize() override;
   void GrabServer() override;
   void UngrabServer() override;
   bool TakeDisplayControl() override;
   bool RelinquishDisplayControl() override;
   void SyncWithServer() override;
   void SetBackgroundColor(uint32_t color_argb) override;
@@ skipping 31 matching lines @@
   void OnUpdateNativeDisplays(
       const std::vector<DisplaySnapshot_Params>& displays);
   void OnDisplayConfigured(int64_t display_id, bool status);
 
   void OnNewGraphicsDevice(const base::FilePath& path, base::File file);
 
   DriGpuPlatformSupportHost* proxy_;  // Not owned.
   DeviceManager* device_manager_;     // Not owned.
   DisplayManager* display_manager_;   // Not owned.
 
+  // File path for the primary graphics card which is opened by default in the
+  // GPU process. We'll avoid opening this in hotplug events since it will race
+  // with the GPU process trying to open it and aquire DRM master.
+  const base::FilePath primary_graphics_card_path_;
+
   // Keeps track if there is a dummy display. This happens on initialization
   // when there is no connection to the GPU to update the displays.
   bool has_dummy_display_;
 
   ScopedVector<DisplaySnapshot> displays_;
   ObserverList<NativeDisplayObserver> observers_;
 
   GetDisplaysCallback get_displays_callback_;
 
   // Map between display_id and the configuration callback.
   std::map<int64_t, ConfigureCallback> configure_callback_map_;
 
   base::WeakPtrFactory<NativeDisplayDelegateProxy> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeDisplayDelegateProxy);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_NATIVE_DISPLAY_DELEGATE_PROXY_H_