Added Ash.SystemMenu.DefaultView.VisibleItems histogram.

ash/common/system/tray/tray_details_view_unittest.cc

 // Copyright 2013 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/tray_details_view.h"
 
 #include "ash/common/system/tray/hover_highlight_view.h"
 #include "ash/common/system/tray/special_popup_row.h"
 #include "ash/common/system/tray/system_tray.h"
 #include "ash/common/system/tray/system_tray_item.h"
@@ skipping 47 matching lines @@
  private:
   TrayPopupHeaderButton* tray_popup_header_button_;
 
   DISALLOW_COPY_AND_ASSIGN(TestDetailsView);
 };
 
 // Trivial item implementation that tracks its views for testing.
 class TestItem : public SystemTrayItem {
  public:
   TestItem()
-      : SystemTrayItem(AshTestBase::GetPrimarySystemTray()),
+      : SystemTrayItem(AshTestBase::GetPrimarySystemTray(), UMA_TEST),
         tray_view_(nullptr),
         default_view_(nullptr),
         detailed_view_(nullptr) {}
 
   // Overridden from SystemTrayItem:
   views::View* CreateTrayView(LoginStatus status) override {
     tray_view_ = new views::View;
     return tray_view_;
   }
   views::View* CreateDefaultView(LoginStatus status) override {
@@ skipping 185 matching lines @@
   gfx::Rect bounds = button->GetBoundsInScreen();
   gfx::Point initial_point(bounds.x() - 1, bounds.y());
   generator.set_current_location(initial_point);
   generator.MoveMouseBy(1, 0);
   RunAllPendingInMessageLoop();
   EXPECT_TRUE(button->background());
 }
 
 }  // namespace test
 }  // namespace ash