Added Ash.SystemMenu.DefaultView.VisibleItems histogram.

ash/common/system/tray/system_tray_bubble.h

 // 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.
 
 #ifndef ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_BUBBLE_H_
 #define ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_BUBBLE_H_
 
+#include <map>
 #include <memory>
 #include <vector>
 
 #include "ash/common/login_status.h"
+#include "ash/common/system/tray/system_tray_item.h"
 #include "base/macros.h"
 #include "base/timer/timer.h"
 #include "ui/views/bubble/tray_bubble_view.h"
 
 namespace ash {
 class SystemTray;
 class SystemTrayItem;
 
 class SystemTrayBubble {
  public:
@@ skipping 30 matching lines @@
   void StopAutoCloseTimer();
   void RestartAutoCloseTimer();
   void Close();
   void SetVisible(bool is_visible);
   bool IsVisible();
 
   // Returns true if any of the SystemTrayItems return true from
   // ShouldShowShelf().
   bool ShouldShowShelf() const;
 
+  // Records metrics for visible system menu rows. Only implemented for the
+  // BUBBLE_TYPE_DEFAULT BubbleType.
+  void RecordVisibleRowMetrics();
+
  private:
   void CreateItemViews(LoginStatus login_status);
 
   ash::SystemTray* tray_;
   views::TrayBubbleView* bubble_view_;
   std::vector<ash::SystemTrayItem*> items_;
   BubbleType bubble_type_;
 
+  // Tracks the views created in the last call to CreateItemViews().
+  std::map<SystemTrayItem::UmaType, views::View*> tray_item_view_map_;
+
   int autoclose_delay_;
   base::OneShotTimer autoclose_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayBubble);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_BUBBLE_H_