ash: Fix setting the tray-widget size when tray-view for date changes.

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_
 #pragma once
 
 #include "ash/system/tray/tray_views.h"
 #include "base/i18n/time_formatting.h"
@@ skipping 18 matching lines @@
   void UpdateText();
 
  protected:
   BaseDateTimeView();
 
  private:
   // Updates labels to display the current time.
   virtual void UpdateTextInternal(const base::Time& now) = 0;
 
   // Overridden from views::View.
+  virtual void ChildPreferredSizeChanged(views::View* child) OVERRIDE;
   virtual void OnLocaleChanged() OVERRIDE;
 
   base::OneShotTimer<BaseDateTimeView> timer_;
 
   DISALLOW_COPY_AND_ASSIGN(BaseDateTimeView);
 };
 
 // Popup view used to display the date and day of week.
 class DateView : public BaseDateTimeView {
  public:
@@ skipping 43 matching lines @@
   base::HourClockType hour_type_;
 
   DISALLOW_COPY_AND_ASSIGN(TimeView);
 };
 
 }  // namespace tray
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_DATE_DATE_VIEW_H_