Remove unused references to NativeTheme in TrayPopupItemStyle.

ash/common/system/chromeos/power/power_status_view.h

 // Copyright (c) 2012 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 ASH_COMMON_SYSTEM_CHROMEOS_POWER_POWER_STATUS_VIEW_H_
 #define ASH_COMMON_SYSTEM_CHROMEOS_POWER_POWER_STATUS_VIEW_H_
 
 #include "ash/ash_export.h"
 #include "ash/common/system/chromeos/power/power_status.h"
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "ui/views/view.h"
 
 namespace views {
 class ImageView;
 class Label;
 }
 
 namespace ash {
 
 class ASH_EXPORT PowerStatusView : public views::View,
                                    public PowerStatus::Observer {
  public:
   explicit PowerStatusView(bool default_view_right_align);
   ~PowerStatusView() override;
 
   // views::View:
   void Layout() override;
-  void OnNativeThemeChanged(const ui::NativeTheme* theme) override;
   void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
 
   // PowerStatus::Observer:
   void OnPowerStatusChanged() override;
 
  private:
   friend class PowerStatusViewTest;
 
   void LayoutView();
   void UpdateText();
-  void UpdateStyle();
 
   // views::View:
   void ChildPreferredSizeChanged(views::View* child) override;
 
   // Layout default view UI items on the right side of system tray pop up item
   // if true; otherwise, layout the UI items on the left side.
   bool default_view_right_align_;
 
   views::Label* percentage_label_;
   views::Label* separator_label_;
   views::Label* time_status_label_;
 
   // Battery status indicator icon. Unused in material design.
   views::ImageView* icon_;
 
   // Information about the image last used to update |icon_|. Cached to avoid
   // unnecessary updates (http://crbug.com/589348).
   PowerStatus::BatteryImageInfo previous_battery_image_info_;
 
   // Only used in material design.
   base::string16 accessible_name_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerStatusView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_CHROMEOS_POWER_POWER_STATUS_VIEW_H_