drm: Make DrmDisplayHostManager handle VGEM fd by itself.

ui/ozone/platform/drm/host/drm_display_host_manager.h

Index: ui/ozone/platform/drm/host/drm_display_host_manager.h
diff --git a/ui/ozone/platform/drm/host/drm_display_host_manager.h b/ui/ozone/platform/drm/host/drm_display_host_manager.h
index f5ae2b831e31e363215787c1e18056afde726ef9..1c7c3af21dba5809c33a99fef6de8d27fef6d910 100644
--- a/ui/ozone/platform/drm/host/drm_display_host_manager.h
+++ b/ui/ozone/platform/drm/host/drm_display_host_manager.h
@@ -107,6 +107,9 @@ class DrmDisplayHostManager : public DeviceEventObserver,
   // with the GPU process trying to open it and aquire DRM master.
   base::FilePath primary_graphics_card_path_;
 
+  // File path for virtual gem device.
+  base::FilePath vgem_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_;
@@ -138,6 +141,9 @@ class DrmDisplayHostManager : public DeviceEventObserver,
   // established.
   scoped_ptr<DrmDeviceHandle> primary_drm_device_handle_;
 
+  // Manages the VGEM device by itself and doesn't send it to GPU process.
+  base::File vgem_card_device_file_;
+
   base::WeakPtrFactory<DrmDisplayHostManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DrmDisplayHostManager);