Remove scoped_ptr for system tray views

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 83bf27cbb89df3c7ea8ee2608778aa16af44516d..f1659241c4249869fb4a90c5a397173e440ddb54 100644
--- a/ash/system/audio/tray_volume.h
+++ b/ash/system/audio/tray_volume.h
@@ -8,7 +8,6 @@
 
 #include "ash/system/audio/audio_observer.h"
 #include "ash/system/tray/tray_image_item.h"
-#include "base/memory/scoped_ptr.h"
 
 namespace ash {
 namespace internal {
@@ -36,7 +35,7 @@ class TrayVolume : public TrayImageItem,
   // Overridden from AudioObserver.
   virtual void OnVolumeChanged(float percent) OVERRIDE;
 
-  scoped_ptr<tray::VolumeView> volume_view_;
+  tray::VolumeView* volume_view_;
 
   // Was |volume_view_| created for CreateDefaultView() rather than
   // CreateDetailedView()?  Used to avoid resetting |volume_view_|