Added Ash.SystemMenu.DefaultView.VisibleItems histogram.

ash/common/system/chromeos/network/tray_vpn.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/network/tray_vpn.h"
 
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/system/chromeos/network/network_state_list_detailed_view.h"
 #include "ash/common/system/chromeos/network/vpn_delegate.h"
 #include "ash/common/system/tray/system_tray.h"
@@ skipping 94 matching lines @@
           vpn, ui::network_icon::ICON_TYPE_DEFAULT_VIEW);
     }
   }
 
   DISALLOW_COPY_AND_ASSIGN(VpnDefaultView);
 };
 
 }  // namespace tray
 
 TrayVPN::TrayVPN(SystemTray* system_tray)
-    : SystemTrayItem(system_tray), default_(NULL), detailed_(NULL) {
+    : SystemTrayItem(system_tray, UMA_VPN),
+      default_(nullptr),
+      detailed_(nullptr) {
   network_state_observer_.reset(new TrayNetworkStateObserver(this));
 }
 
 TrayVPN::~TrayVPN() {}
 
 views::View* TrayVPN::CreateTrayView(LoginStatus status) {
   return NULL;
 }
 
 views::View* TrayVPN::CreateDefaultView(LoginStatus status) {
@@ skipping 41 matching lines @@
 void TrayVPN::UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) {}
 
 void TrayVPN::NetworkStateChanged() {
   if (default_)
     default_->Update();
   if (detailed_)
     detailed_->Update();
 }
 
 }  // namespace ash