Stop using shell::GetInstance()->system_tray() in system tray items

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"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 
 namespace views {
 class View;
 }
 
 namespace ash {
 
+class SystemTray;

[msw, 2012/11/16 17:10:06]

nit: this forward decl should make a lot of the others unnecessary.
(many of the files touched include this file)

[bartfab (slow), 2012/11/16 17:16:01]

It does make them unnecessary in that the forward declaration happens to be
pulled in, sometimes via multiple steps of inclusion. However, as the style
guide rule is to directly include (or forward declare) all that you use, I
explicitly forward declared the class in the other headers as well.

On 2012/11/16 17:10:06, msw wrote:

[msw, 2012/11/16 17:41:35]

True, but for some straightforward cases, you can skip this. For example, not
every user of ui/gfx/rect.h needs to include point.h and size.h for those
fundamental underpinnings of Rect. That said, it's just a nit, and you're free
to ignore me :)

[stevenjb, 2012/11/16 17:41:43]

I mentioned this earlier also. Forward declarations work like #incldues. If A
includes B which includes C, A does not always need to include C (e.g. if A
derives from B derives from C, generally A only includes B). Use good judgement
here. In this case, SystemTray is part of the constructor for SystemTrayItem, so
anything that includes system_tray_item.h can safely assume that SystemTray will
remain declared; the declaration can not be removed without changing the
constructor and thus all dependent files.

[bartfab (slow), 2012/11/16 18:45:34]

Done.

+
 namespace internal {
 class TrayItemView;
 }
 
 class ASH_EXPORT SystemTrayItem {
  public:
-  SystemTrayItem();
+  explicit SystemTrayItem(SystemTray* system_tray);
   virtual ~SystemTrayItem();
 
   // Create* functions may return NULL if nothing should be displayed for the
   // type of view. The default implementations return NULL.
 
   // Returns a view to be displayed in the system tray. If this returns NULL,
   // then this item is not displayed in the tray.
   // NOTE: The returned view should almost always be a TrayItemView, which
   // automatically resizes the widget when the size of the view changes, and
   // adds animation when the visibility of the view changes. If a view wants to
@@ skipping 56 matching lines @@
   // Shows a notification for this item.
   void ShowNotificationView();
 
   // Hides the notification for this item.
   void HideNotificationView();
 
   // Returns true if this item needs to force the launcher to be visible when
   // the launcher is in the auto-hide state. Default is true.
   virtual bool ShouldShowLauncher() const;
 
+  // Returns the system tray that this item belongs to.
+  SystemTray* system_tray() const { return system_tray_; }
+
  private:
+  SystemTray* system_tray_;
+
   DISALLOW_COPY_AND_ASSIGN(SystemTrayItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_