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

ash/system/audio/tray_volume.h

Index: ash/system/audio/tray_volume.h
diff --git a/ash/system/audio/tray_volume.h b/ash/system/audio/tray_volume.h
index ddb9fd1c2192d335c1a3d80dc5502e713de25c49..4afe1f7badf217d95a02098de169bf0cd355b8e1 100644
--- a/ash/system/audio/tray_volume.h
+++ b/ash/system/audio/tray_volume.h
@@ -9,6 +9,9 @@
 #include "ash/system/tray/tray_image_item.h"
 
 namespace ash {
+
+class SystemTray;

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

nit: SystemTray is part of the base class constructor, so doesn't really need to
be forward declared here and elsewhere.

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

Done.

+
 namespace internal {
 
 namespace tray {
@@ -18,7 +21,7 @@ class VolumeView;
 class TrayVolume : public TrayImageItem,
                    public AudioObserver {
  public:
-  TrayVolume();
+  explicit TrayVolume(SystemTray* system_tray);
   virtual ~TrayVolume();
 
  private: