Added Ash.SystemMenu.DefaultView.VisibleItems histogram.

ash/test/test_system_tray_item.h

Index: ash/test/test_system_tray_item.h
diff --git a/ash/test/test_system_tray_item.h b/ash/test/test_system_tray_item.h
new file mode 100644
index 0000000000000000000000000000000000000000..888e249f4da58b04761724beb814017ce876db72
--- /dev/null
+++ b/ash/test/test_system_tray_item.h
@@ -0,0 +1,56 @@
+// Copyright 2016 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_TEST_TEST_SYSTEM_TRAY_ITEM_H_
+#define ASH_COMMON_SYSTEM_TRAY_TEST_TEST_SYSTEM_TRAY_ITEM_H_
+
+#include "ash/common/system/tray/system_tray_item.h"
+
+namespace ash {
+namespace test {
+
+// Trivial item implementation that tracks its views for testing. By default
+// views are created and returned by the Create*View() methods and they are
+// configured to be visible. Use set_has_views() and set_views_are_visible() to
+// change this behavior.
+class TestSystemTrayItem : public SystemTrayItem {
+ public:
+  TestSystemTrayItem();
+  explicit TestSystemTrayItem(SystemTrayItem::UmaType uma_type);
+  ~TestSystemTrayItem() override;
+
+  void set_has_views(bool has_views) { has_views_ = has_views; }
+  void set_views_are_visible(bool visible) { views_are_visible_ = visible; }
+
+  views::View* tray_view() const { return tray_view_; }
+  views::View* default_view() const { return default_view_; }
+  views::View* detailed_view() const { return detailed_view_; }
+  views::View* notification_view() const { return notification_view_; }
+
+  // SystemTrayItem:
+  views::View* CreateTrayView(LoginStatus status) override;
+  views::View* CreateDefaultView(LoginStatus status) override;
+  views::View* CreateDetailedView(LoginStatus status) override;
+  views::View* CreateNotificationView(LoginStatus status) override;
+  void DestroyTrayView() override;
+  void DestroyDefaultView() override;
+  void DestroyDetailedView() override;
+  void DestroyNotificationView() override;
+  void UpdateAfterLoginStatusChange(LoginStatus status) override;
+
+ private:
+  bool has_views_;
+  bool views_are_visible_;
+  views::View* tray_view_;
+  views::View* default_view_;
+  views::View* detailed_view_;
+  views::View* notification_view_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestSystemTrayItem);
+};
+
+}  // namespace test
+}  // namespace ash
+
+#endif  // ASH_COMMON_SYSTEM_TRAY_TEST_TEST_SYSTEM_TRAY_ITEM_H_