Consolidate volume control code.

ash/system/tray/system_tray_item.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_SYSTEM_TRAY_ITEM_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/user/login_status.h"
 #include "ash/wm/shelf_types.h"
@@ skipping 49 matching lines @@
   // Updates the tray view (if applicable) when the user's login status changes.
   // It is not necessary the update the default or detailed view, since the
   // default/detailed popup is closed when login status changes. The default
   // implementation does nothing.
   virtual void UpdateAfterLoginStatusChange(user::LoginStatus status);
 
   // Updates the tray view (if applicable) when shelf's alignment changes.
   // The default implementation does nothing.
   virtual void UpdateAfterShelfAlignmentChange(ShelfAlignment alignment);
 
+  // Updates the tray view after the ash shell has been initialized.
+  virtual void UpdateAfterAshInit();

[sadrul, 2012/08/09 18:05:33]

I don't think we should have this. Or if we do have this, we should get rid of
GetInitialVisibility.

Ideally, all the things that the tray depends on, i.e. the volume-controller
etc., should be created with the tray-delegate (i.e. before the tray itself is
created), so that this problem does not show up. (perhaps create the
VolumeController etc. when the SystemTrayDelegate is created) What do you think?

[jennyz, 2012/08/13 23:26:17]

yes, I think your suggestion is reasonable. Now I move the VolumeControlDelegate
to SystemTrayDelegate, and removed UpdateAfterAshInit. Also I created a
DummyVolumeControlDelegate to be initialized by DummySystemTrayDelegate which
makes ash_unittests happy. I think we probably should do the same refactoring to
other device control delegate, such as BrightnessControlDelegate, etc. What do
you think?

+
   // Shows the detailed view for this item. If the main popup for the tray is
   // currently visible, then making this call would use the existing window to
   // display the detailed item. The detailed item will inherit the bounds of the
   // existing window.
   // If there is no existing view, then this is equivalent to calling
   // PopupDetailedView(0, true).
   void TransitionDetailedView();
 
   // Pops up the detailed view for this item. An item can request to show its
   // detailed view using this function (e.g. from an observer callback when
@@ skipping 17 matching lines @@
   void HideNotificationView();
 
  private:
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_