[3/4][Ozone-Drm] Use numeric ID to map to callback

ui/ozone/platform/drm/gpu/drm_device.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_DRM_DEVICE_H_
 #define UI_OZONE_PLATFORM_DRM_GPU_DRM_DEVICE_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 159 matching lines @@
 
  protected:
   friend class base::RefCountedThreadSafe<DrmDevice>;
 
   virtual ~DrmDevice();
 
   scoped_ptr<HardwareDisplayPlaneManager> plane_manager_;
 
  private:
   class IOWatcher;
+  class PageFlipManager;
 
   // Path to DRM device.
   const base::FilePath device_path_;
 
   // DRM device.
   base::File file_;
 
   // Helper thread to perform IO listener operations.
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   // Watcher for |fd_| listening for page flip events.
   scoped_refptr<IOWatcher> watcher_;
 
+  scoped_refptr<PageFlipManager> page_flip_manager_;
+
   DISALLOW_COPY_AND_ASSIGN(DrmDevice);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRM_GPU_DRM_DEVICE_H_