Figure out the default graphics card on the Browser process

ui/ozone/platform/dri/native_display_delegate_proxy.h

Index: ui/ozone/platform/dri/native_display_delegate_proxy.h
diff --git a/ui/ozone/platform/dri/native_display_delegate_proxy.h b/ui/ozone/platform/dri/native_display_delegate_proxy.h
index 70f1e8fedb51cd32b7d2de347a99a66d3fe68065..324c737692bba5c15886828a11bc2beceff59257 100644
--- a/ui/ozone/platform/dri/native_display_delegate_proxy.h
+++ b/ui/ozone/platform/dri/native_display_delegate_proxy.h
@@ -8,6 +8,7 @@
 #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"
@@ -29,7 +30,8 @@ class NativeDisplayDelegateProxy : public NativeDisplayDelegate,
  public:
   NativeDisplayDelegateProxy(DriGpuPlatformSupportHost* proxy,
                              DeviceManager* device_manager,
-                             DisplayManager* display_manager);
+                             DisplayManager* display_manager,
+                             const base::FilePath& primary_graphics_card_path);
   ~NativeDisplayDelegateProxy() override;
 
   // NativeDisplayDelegate overrides:
@@ -81,6 +83,11 @@ class NativeDisplayDelegateProxy : public NativeDisplayDelegate,
   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_;