Switch DRM platform to using a separate thread

ui/ozone/platform/drm/gpu/gbm_surfaceless.h

Index: ui/ozone/platform/drm/gpu/gbm_surfaceless.h
diff --git a/ui/ozone/platform/drm/gpu/gbm_surfaceless.h b/ui/ozone/platform/drm/gpu/gbm_surfaceless.h
index d050d256c2f8c724504e17ae3a46fdd01c2f1a94..085a4acc71ad7f281027cc32304183e8410fe072 100644
--- a/ui/ozone/platform/drm/gpu/gbm_surfaceless.h
+++ b/ui/ozone/platform/drm/gpu/gbm_surfaceless.h
@@ -7,17 +7,18 @@
 
 #include <vector>
 
+#include "ui/gfx/native_widget_types.h"
 #include "ui/ozone/platform/drm/gpu/overlay_plane.h"
 #include "ui/ozone/public/surface_ozone_egl.h"
 
 namespace gfx {
 class Size;
-}  // namespace gfx
+}
 
 namespace ui {
 
 class DrmDeviceManager;
-class DrmWindow;
+class DrmWindowProxy;
 class GbmSurfaceFactory;
 
 // In surfaceless mode drawing and displaying happens directly through
@@ -26,9 +27,9 @@ class GbmSurfaceFactory;
 // presentation.
 class GbmSurfaceless : public SurfaceOzoneEGL {
  public:
-  GbmSurfaceless(DrmWindow* window,
-                 DrmDeviceManager* drm_device_manager,
-                 GbmSurfaceFactory* surface_manager);
+  GbmSurfaceless(scoped_ptr<DrmWindowProxy> window,
+                 GbmSurfaceFactory* surface_manager,
+                 DrmDeviceManager* device_manager);
   ~GbmSurfaceless() override;
 
   void QueueOverlayPlane(const OverlayPlane& plane);
@@ -42,9 +43,12 @@ class GbmSurfaceless : public SurfaceOzoneEGL {
   bool IsUniversalDisplayLinkDevice() override;
 
  protected:
-  DrmWindow* window_;
-  DrmDeviceManager* drm_device_manager_;
+  scoped_ptr<DrmWindowProxy> window_;
+
   GbmSurfaceFactory* surface_manager_;
+
+  DrmDeviceManager* device_manager_;
+
   std::vector<OverlayPlane> planes_;
 
   DISALLOW_COPY_AND_ASSIGN(GbmSurfaceless);