mash: Move TrayTracing to //ash/common/system/chromeos

ash/system/chromeos/tray_tracing.h

-// Copyright 2013 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_TRACING_H_
-#define ASH_SYSTEM_TRAY_TRACING_H_
-
-#include "ash/ash_export.h"
-#include "ash/common/system/tray/tray_image_item.h"
-#include "base/macros.h"
-
-namespace views {
-class View;
-}
-
-namespace ash {
-
-class ASH_EXPORT TracingObserver {
- public:
-  virtual ~TracingObserver() {}
-
-  // Notifies when tracing mode changes.
-  virtual void OnTracingModeChanged(bool value) = 0;
-};
-
-// This is the item that displays when users enable performance tracing at
-// chrome://slow.  It alerts them that this mode is running, and provides an
-// easy way to open the page to disable it.
-class TrayTracing : public TrayImageItem,
-                    public TracingObserver {
- public:
-  explicit TrayTracing(SystemTray* system_tray);
-  ~TrayTracing() override;
-
- private:
-  void SetTrayIconVisible(bool visible);
-
-  // Overridden from TrayImageItem.
-  bool GetInitialVisibility() override;
-  views::View* CreateDefaultView(LoginStatus status) override;
-  views::View* CreateDetailedView(LoginStatus status) override;
-  void DestroyDefaultView() override;
-  void DestroyDetailedView() override;
-
-  // Overridden from TracingObserver.
-  void OnTracingModeChanged(bool value) override;
-
-  views::View* default_;
-
-  DISALLOW_COPY_AND_ASSIGN(TrayTracing);
-};
-
-}  // namespace ash
-
-#endif  // ASH_SYSTEM_TRAY_TRACING_H_