Fix namespace for src/ui/display/.

ui/ozone/common/display_mode_proxy.cc

 // 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.
 
 #include "base/memory/ptr_util.h"
 
 #include "ui/ozone/common/display_mode_proxy.h"
 
 #include "ui/ozone/common/gpu/ozone_gpu_message_params.h"
 
 namespace ui {
 
 DisplayModeProxy::DisplayModeProxy(const DisplayMode_Params& params)
     : DisplayMode(params.size, params.is_interlaced, params.refresh_rate) {
 }
 
 DisplayModeProxy::DisplayModeProxy(const gfx::Size& size,
                                    bool interlaced,
                                    float refresh_rate)
     : DisplayMode(size, interlaced, refresh_rate) {}
 
 DisplayModeProxy::~DisplayModeProxy() {
 }
 
-std::unique_ptr<DisplayMode> DisplayModeProxy::Clone() const {
+std::unique_ptr<display::DisplayMode> DisplayModeProxy::Clone() const {
   return base::WrapUnique(
       new DisplayModeProxy(size(), is_interlaced(), refresh_rate()));
 }
 
 }  // namespace ui