cros: Remove supervised user methods from SystemTrayDelegate

ash/system/tray/label_tray_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_LABEL_TRAY_VIEW_H_
 #define ASH_SYSTEM_TRAY_LABEL_TRAY_VIEW_H_
 
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "ui/views/view.h"
 
 namespace gfx {
 struct VectorIcon;
 }  // namespace gfx
 
 namespace ash {
 class ViewClickListener;
 
 // A view to display an icon and message text in the system menu which
 // automatically hides when the message text is empty. Multi-line message text
 // is supported.
 class LabelTrayView : public views::View {
  public:
+  // If |click_listener| is null then no action is taken on click.
   LabelTrayView(ViewClickListener* click_listener, const gfx::VectorIcon& icon);
   ~LabelTrayView() override;
+
+  const base::string16& message() { return message_; }
+
   void SetMessage(const base::string16& message);
 
  private:
   views::View* CreateChildView(const base::string16& message) const;
 
   ViewClickListener* click_listener_;
   const gfx::VectorIcon& icon_;
   base::string16 message_;
 
   DISALLOW_COPY_AND_ASSIGN(LabelTrayView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_LABEL_TRAY_VIEW_H_