Added Ash.SystemMenu.DefaultView.VisibleItems histogram.

ash/common/system/chromeos/media_security/multi_profile_media_tray_item.cc

 // Copyright 2014 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.
 
 #include "ash/common/system/chromeos/media_security/multi_profile_media_tray_item.h"
 
 #include "ash/common/ash_view_ids.h"
 #include "ash/common/media_delegate.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/system/chromeos/media_security/media_capture_observer.h"
@@ skipping 44 matching lines @@
     SetVisible(false);
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MultiProfileMediaTrayView);
 };
 
 }  // namespace tray
 
 MultiProfileMediaTrayItem::MultiProfileMediaTrayItem(SystemTray* system_tray)
-    : SystemTrayItem(system_tray), tray_view_(nullptr) {}
+    : SystemTrayItem(system_tray, UMA_MULTI_PROFILE_MEDIA),
+      tray_view_(nullptr) {}
 
 MultiProfileMediaTrayItem::~MultiProfileMediaTrayItem() {}
 
 views::View* MultiProfileMediaTrayItem::CreateTrayView(LoginStatus status) {
   tray_view_ = new tray::MultiProfileMediaTrayView(this);
   return tray_view_;
 }
 
 void MultiProfileMediaTrayItem::DestroyTrayView() {
   tray_view_ = nullptr;
 }
 
 }  // namespace ash