Add a row in the network tray to inform users to turn Bluetooth on to enable Tether.

ash/system/tray/tray_details_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_SYSTEM_TRAY_TRAY_DETAILS_VIEW_H_
 #define ASH_SYSTEM_TRAY_TRAY_DETAILS_VIEW_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/view_click_listener.h"
 #include "base/macros.h"
 #include "base/timer/timer.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/view.h"
 
 namespace gfx {
 struct VectorIcon;
 }  // namespace gfx
 
 namespace views {
 class BoxLayout;
 class CustomButton;
-class Label;
 class ProgressBar;
 class ScrollView;
 }  // namespace views
 
 namespace ash {
 
 class HoverHighlightView;
 class ScrollBorder;
 class SystemTrayItem;
 class TriView;
 
 class ASH_EXPORT TrayDetailsView : public views::View,
                                    public ViewClickListener,
                                    public views::ButtonListener {
  public:
   explicit TrayDetailsView(SystemTrayItem* owner);
   ~TrayDetailsView() override;
 
   // ViewClickListener:
   // Don't override this --- override HandleViewClicked.
   void OnViewClicked(views::View* sender) final;
 
   // views::ButtonListener:
   // Don't override this --- override HandleButtonPressed.
   void ButtonPressed(views::Button* sender, const ui::Event& event) final;
 
   SystemTrayItem* owner() { return owner_; }
 
  protected:
-  // A view containing only a label, which is to be inserted as a non-targetable
-  // row within a system menu detailed view (e.g., the "Scanning for devices..."
-  // message that can appear at the top of the Bluetooth detailed view).
-  class InfoLabel : public View {
-   public:
-    explicit InfoLabel(int message_id);
-    ~InfoLabel() override;
-
-    void SetMessage(int message_id);
-
-   private:
-    views::Label* const label_;
-
-    DISALLOW_COPY_AND_ASSIGN(InfoLabel);
-  };
-
   // views::View:
   void Layout() override;
   int GetHeightForWidth(int width) const override;
 
   // Exposes the layout manager of this view to give control to subclasses.
   views::BoxLayout* box_layout() { return box_layout_; }
 
   // Creates the row containing the back button and title. For material design
   // this appears at the top of the view, for non-material design it appears
   // at the bottom.
@@ skipping 95 matching lines @@
 
   // Used to delay the transition to the default view.
   base::OneShotTimer transition_delay_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayDetailsView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_TRAY_DETAILS_VIEW_H_