Template methods on Timer classes instead of the classes themselves.

ash/system/date/date_view.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_SYSTEM_DATE_DATE_VIEW_H_
 #define ASH_SYSTEM_DATE_DATE_VIEW_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/date/tray_date.h"
 #include "ash/system/tray/actionable_view.h"
@@ skipping 26 matching lines @@
   void SetTimer(const base::Time& now);
 
   // Updates labels to display the current time.
   virtual void UpdateTextInternal(const base::Time& now) = 0;
 
   // Overridden from views::View.
   void ChildPreferredSizeChanged(views::View* child) override;
   void OnLocaleChanged() override;
 
   // Invokes UpdateText() when the displayed time should change.
-  base::OneShotTimer<BaseDateTimeView> timer_;
+  base::OneShotTimer timer_;
 
   DISALLOW_COPY_AND_ASSIGN(BaseDateTimeView);
 };
 
 // Popup view used to display the date and day of week.
 class ASH_EXPORT DateView : public BaseDateTimeView {
  public:
   DateView();
   ~DateView() override;
 
@@ skipping 72 matching lines @@
 
   base::HourClockType hour_type_;
 
   DISALLOW_COPY_AND_ASSIGN(TimeView);
 };
 
 }  // namespace tray
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_DATE_DATE_VIEW_H_