Migrate simple ash Shell metrics users.

ash/system/chromeos/audio/tray_audio_chromeos.cc

Index: ash/system/chromeos/audio/tray_audio_chromeos.cc
diff --git a/ash/system/chromeos/audio/tray_audio_chromeos.cc b/ash/system/chromeos/audio/tray_audio_chromeos.cc
index cca87c8d2183025e3982d63efa2274a29d7410cd..0fd8dd56a9c631e3a88fbfe8f0fcdeace2577891 100644
--- a/ash/system/chromeos/audio/tray_audio_chromeos.cc
+++ b/ash/system/chromeos/audio/tray_audio_chromeos.cc
@@ -5,8 +5,7 @@
 #include "ash/system/chromeos/audio/tray_audio_chromeos.h"
 
 #include "ash/common/system/audio/volume_view.h"
-#include "ash/metrics/user_metrics_recorder.h"
-#include "ash/shell.h"
+#include "ash/common/wm_shell.h"
 #include "ash/system/chromeos/audio/audio_detailed_view.h"
 #include "ash/system/chromeos/audio/tray_audio_delegate_chromeos.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
@@ -43,8 +42,8 @@ views::View* TrayAudioChromeOs::CreateDetailedView(LoginStatus status) {
     volume_view_ = new tray::VolumeView(this, audio_delegate_.get(), false);
     return volume_view_;
   } else {
-    Shell::GetInstance()->metrics()->RecordUserMetricsAction(
-        ash::UMA_STATUS_AREA_DETAILED_AUDIO_VIEW);
+    WmShell::Get()->RecordUserMetricsAction(
+        UMA_STATUS_AREA_DETAILED_AUDIO_VIEW);
     audio_detail_view_ = new tray::AudioDetailedView(this);
     return audio_detail_view_;
   }