Switch DRM platform to using a separate thread

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_OZONE_PLATFORM_DRM_GPU_GBM_SURFACE_FACTORY_H_
 #define UI_OZONE_PLATFORM_DRM_GPU_GBM_SURFACE_FACTORY_H_
 
 #include "base/threading/thread_checker.h"
 #include "ui/ozone/public/surface_factory_ozone.h"
 
 namespace ui {
 
-class DrmDeviceManager;
-class DrmWindow;
+class DrmThread;
 class GbmDevice;
-class ScreenManager;
 
 class GbmSurfaceFactory : public SurfaceFactoryOzone {
  public:
-  GbmSurfaceFactory();
+  GbmSurfaceFactory(DrmThread* drm_thread);
   ~GbmSurfaceFactory() override;
 
-  void InitializeGpu(DrmDeviceManager* drm_device_manager,
-                     ScreenManager* screen_manager);
-
-  // DrmSurfaceFactory:
+  // SurfaceFactoryOzone:
   intptr_t GetNativeDisplay() override;
   const int32_t* GetEGLSurfaceProperties(const int32_t* desired_list) override;
   bool LoadEGLGLES2Bindings(
       AddGLLibraryCallback add_gl_library,
       SetGLGetProcAddressProcCallback set_gl_get_proc_address) override;
   scoped_ptr<SurfaceOzoneCanvas> CreateCanvasForWidget(
       gfx::AcceleratedWidget widget) override;
   scoped_ptr<ui::SurfaceOzoneEGL> CreateEGLSurfaceForWidget(
       gfx::AcceleratedWidget w) override;
   scoped_ptr<SurfaceOzoneEGL> CreateSurfacelessEGLSurfaceForWidget(
       gfx::AcceleratedWidget widget) override;
   scoped_refptr<ui::NativePixmap> CreateNativePixmap(
       gfx::AcceleratedWidget widget,
       gfx::Size size,
       gfx::BufferFormat format,
       gfx::BufferUsage usage) override;
 
  private:
   scoped_refptr<GbmDevice> GetGbmDevice(gfx::AcceleratedWidget widget);
 
-  DrmDeviceManager* drm_device_manager_;  // Not owned.
-  ScreenManager* screen_manager_;         // Not owned.
+  base::ThreadChecker thread_checker_;
 
-  base::ThreadChecker thread_checker_;
+  DrmThread* drm_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(GbmSurfaceFactory);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRM_GPU_GBM_SURFACE_FACTORY_H_