Added Ash.SystemMenu.DefaultView.VisibleItems histogram.

ash/common/system/chromeos/enterprise/tray_enterprise.cc

 // 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.
 
 #include "ash/common/system/chromeos/enterprise/tray_enterprise.h"
 
 #include "ash/common/login_status.h"
 #include "ash/common/system/tray/label_tray_view.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/system/tray/system_tray_notifier.h"
 #include "ash/common/wm_shell.h"
 #include "base/logging.h"
 #include "base/strings/string16.h"
 #include "grit/ash_resources.h"
 
 namespace ash {
 
 TrayEnterprise::TrayEnterprise(SystemTray* system_tray)
-    : SystemTrayItem(system_tray), tray_view_(NULL) {
+    : SystemTrayItem(system_tray, UMA_ENTERPRISE), tray_view_(nullptr) {
   WmShell::Get()->system_tray_notifier()->AddEnterpriseDomainObserver(this);
 }
 
 TrayEnterprise::~TrayEnterprise() {
   WmShell::Get()->system_tray_notifier()->RemoveEnterpriseDomainObserver(this);
 }
 
 void TrayEnterprise::UpdateEnterpriseMessage() {
   base::string16 message =
       WmShell::Get()->system_tray_delegate()->GetEnterpriseMessage();
@@ skipping 18 matching lines @@
 
 void TrayEnterprise::OnEnterpriseDomainChanged() {
   UpdateEnterpriseMessage();
 }
 
 void TrayEnterprise::OnViewClicked(views::View* sender) {
   WmShell::Get()->system_tray_delegate()->ShowEnterpriseInfo();
 }
 
 }  // namespace ash