Switch DRM platform to using a separate thread

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

Index: ui/ozone/platform/drm/gpu/drm_window.h
diff --git a/ui/ozone/platform/drm/gpu/drm_window.h b/ui/ozone/platform/drm/gpu/drm_window.h
index a7f4507ac134096a8da13aa2aef0678c7acfb5c6..629fbdcd7badd1721f9dac2c27560750c6ff9f2f 100644
--- a/ui/ozone/platform/drm/gpu/drm_window.h
+++ b/ui/ozone/platform/drm/gpu/drm_window.h
@@ -28,6 +28,7 @@ class Rect;
 namespace ui {
 
 class DrmBuffer;
+class DrmDevice;
 class DrmDeviceManager;
 class HardwareDisplayController;
 struct OverlayCheck_Params;
@@ -67,7 +68,7 @@ class OZONE_EXPORT DrmWindow {
   void SetController(HardwareDisplayController* controller);
 
   // Called when the window is resized/moved.
-  void OnBoundsChanged(const gfx::Rect& bounds);
+  void SetBounds(const gfx::Rect& bounds);
 
   // Update the HW cursor bitmap & move to specified location. If
   // the bitmap is empty, the cursor is hidden.