Added Ash.SystemMenu.DefaultView.VisibleItems histogram.

ash/common/system/tray/system_tray.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/tray/system_tray.h"
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/login_status.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 733 matching lines @@
   // turn off the active tinting of the shelf.
   if (full_system_tray_menu_) {
     SetDrawBackgroundAsActive(false);
     full_system_tray_menu_ = false;
   }
 }
 
 void SystemTray::RecordSystemMenuMetrics() {
   DCHECK(system_bubble_);
 
+  system_bubble_->bubble()->RecordVisibleRowMetrics();
+
   TrayBubbleView* bubble_view = system_bubble_->bubble_view();
   int num_rows = 0;
   for (int i = 0; i < bubble_view->child_count(); i++) {
     // Certain menu rows are attached by default but can set themselves as
     // invisible (IME is one such example). Count only user-visible rows.
     if (bubble_view->child_at(i)->visible())
       num_rows++;
   }
   UMA_HISTOGRAM_COUNTS_100("Ash.SystemMenu.Rows", num_rows);
 
   int work_area_height =
       display::Screen::GetScreen()
           ->GetDisplayNearestWindow(bubble_view->GetWidget()->GetNativeView())
           .work_area()
           .height();
   if (work_area_height > 0) {
     UMA_HISTOGRAM_CUSTOM_COUNTS(
         "Ash.SystemMenu.PercentageOfWorkAreaHeightCoveredByMenu",
         100 * bubble_view->height() / work_area_height, 1, 300, 100);
   }
 }
 
 }  // namespace ash