Fix namespace for src/ui/display/.

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 DisplayMode {
+class DisplayModeProxy : public display::DisplayMode {
  public:
   explicit DisplayModeProxy(const DisplayMode_Params& params);
   ~DisplayModeProxy() override;
-  std::unique_ptr<DisplayMode> Clone() const 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_