Switch DRM platform to using a separate thread

ui/ozone/platform/drm/gpu/drm_surface_factory.cc

Index: ui/ozone/platform/drm/gpu/drm_surface_factory.cc
diff --git a/ui/ozone/platform/drm/gpu/drm_surface_factory.cc b/ui/ozone/platform/drm/gpu/drm_surface_factory.cc
index fc64d2505f3371367216db5050b23cd272625646..a7231a28bafef5e4280b804c357b9ef6563e2f39 100644
--- a/ui/ozone/platform/drm/gpu/drm_surface_factory.cc
+++ b/ui/ozone/platform/drm/gpu/drm_surface_factory.cc
@@ -4,21 +4,17 @@
 
 #include "ui/ozone/platform/drm/gpu/drm_surface_factory.h"
 
-#include <errno.h>
-
 #include "ui/gfx/native_widget_types.h"
-#include "ui/ozone/platform/drm/common/drm_util.h"
 #include "ui/ozone/platform/drm/gpu/drm_surface.h"
-#include "ui/ozone/platform/drm/gpu/drm_window.h"
-#include "ui/ozone/platform/drm/gpu/hardware_display_controller.h"
-#include "ui/ozone/platform/drm/gpu/screen_manager.h"
+#include "ui/ozone/platform/drm/gpu/drm_thread.h"
+#include "ui/ozone/platform/drm/gpu/drm_window_proxy.h"
+#include "ui/ozone/platform/drm/gpu/proxy_helpers.h"
 #include "ui/ozone/public/surface_ozone_canvas.h"
 
 namespace ui {
 
-DrmSurfaceFactory::DrmSurfaceFactory(ScreenManager* screen_manager)
-    : screen_manager_(screen_manager) {
-}
+DrmSurfaceFactory::DrmSurfaceFactory(DrmThread* drm_thread)
+    : drm_thread_(drm_thread) {}
 
 DrmSurfaceFactory::~DrmSurfaceFactory() {
 }
@@ -26,7 +22,8 @@ DrmSurfaceFactory::~DrmSurfaceFactory() {
 scoped_ptr<ui::SurfaceOzoneCanvas> DrmSurfaceFactory::CreateCanvasForWidget(
     gfx::AcceleratedWidget widget) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  return make_scoped_ptr(new DrmSurface(screen_manager_->GetWindow(widget)));
+  return make_scoped_ptr(
+      new DrmSurface(drm_thread_->CreateWindowProxy(widget)));
 }
 
 bool DrmSurfaceFactory::LoadEGLGLES2Bindings(