Add update available icon in system tray

ash/system/update/tray_update.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_UPDATE_TRAY_UPDATE_H_
 #define ASH_SYSTEM_UPDATE_TRAY_UPDATE_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/tray/tray_image_item.h"
 #include "base/gtest_prod_util.h"
@@ skipping 20 matching lines @@
   explicit TrayUpdate(SystemTray* system_tray);
   ~TrayUpdate() override;
 
   // Shows an icon in the system tray indicating that a software update is
   // available. Once shown the icon persists until reboot. |severity| and
   // |factory_reset_required| are used to set the icon, color, and tooltip.
   void ShowUpdateIcon(mojom::UpdateSeverity severity,
                       bool factory_reset_required,
                       mojom::UpdateType update_type);
 
+  // Shows an icon in the system tray indicating that a software update is
+  // available but user's agreement is required as current connection is
+  // cellular. Once shown the icon persists until reboot.
+  void ShowUpdateOverCellularAvailableIcon();
+
  private:
   FRIEND_TEST_ALL_PREFIXES(TrayUpdateTest, VisibilityAfterUpdate);
   FRIEND_TEST_ALL_PREFIXES(TrayUpdateTest, VisibilityAfterFlashUpdate);
 
   class UpdateView;
 
   // Overridden from TrayImageItem.
   bool GetInitialVisibility() override;
   views::View* CreateDefaultView(LoginStatus status) override;
   void DestroyDefaultView() override;
 
   // Expose label information for testing.
   views::Label* GetLabelForTesting();
   UpdateView* update_view_;
 
   // If an external monitor is connected then the system tray may be created
   // after the update data is sent from chrome, so share the update info between
   // all instances.
-  static bool update_required_;
+  static bool upgrade_required_;

[weidongg, 2017/05/15 04:54:13]

I refactored here to distinguish 'update' with 'upgrade'. It seems upgrade does
not include the downloading process of a software update, but I am not sure.

   static mojom::UpdateSeverity severity_;
   static bool factory_reset_required_;
   static mojom::UpdateType update_type_;
+  static bool update_over_cellular_available_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayUpdate);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_UPDATE_TRAY_UPDATE_H_