Delete unnecessary mode code in ozone/drm

ui/ozone/common/display_mode_proxy.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_COMMON_DISPLAY_MODE_PROXY_H_
-#define UI_OZONE_COMMON_DISPLAY_MODE_PROXY_H_
-
-#include "base/macros.h"
-#include "ui/display/types/display_mode.h"
-
-namespace ui {
-
-struct DisplayMode_Params;
-
-class DisplayModeProxy : public display::DisplayMode {
- public:
-  explicit DisplayModeProxy(const DisplayMode_Params& params);
-  ~DisplayModeProxy() override;
-  std::unique_ptr<display::DisplayMode> Clone() const override;
-
- private:
-  DisplayModeProxy(const gfx::Size& size, bool interlaced, float refresh_rate);
-
-  DISALLOW_COPY_AND_ASSIGN(DisplayModeProxy);
-};
-
-}  // namespace ui
-
-#endif  // UI_OZONE_COMMON_DISPLAY_MODE_PROXY_H_