[ash-md] Added a delay between system menu default/detailed view transitions.

ash/common/system/tray/tray_details_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_COMMON_SYSTEM_TRAY_TRAY_DETAILS_VIEW_H_
 #define ASH_COMMON_SYSTEM_TRAY_TRAY_DETAILS_VIEW_H_
 
+#include <memory>
+
 #include "ash/ash_export.h"
 #include "ash/common/system/tray/special_popup_row.h"
+#include "ash/common/system/tray/tray_constants.h"
 #include "ash/common/system/tray/view_click_listener.h"
 #include "base/macros.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/view.h"
 
+namespace base {
+class OneShotTimer;
+}  // namespace base
+
 namespace views {
 class BoxLayout;
 class ScrollView;
 class ProgressBar;
 }  // namespace views
 
 namespace ash {
 namespace test {
 class TrayDetailsViewTest;
 }  // namespace test
@@ skipping 57 matching lines @@
   // Overridden to handle button presses on subclass-specific buttons.
   virtual void HandleButtonPressed(views::Button* sender,
                                    const ui::Event& event);
 
   // Creates and adds subclass-specific buttons to the title row.
   virtual void CreateExtraTitleRowButtons();
 
   // Transition to default view from details view. If |title_row_| has focus
   // before transition, the default view should focus on the owner of this
   // details view.
+  //
+  // In Material Design the actual transition is intentionally delayed to allow
+  // the user to perceive the ink drop animation on the clicked target.
   void TransitionToDefaultView();
 
+  // Actually transitions to the default view.
+  void DoTransitionToDefaultView();
+
   SystemTrayItem* owner_;
   views::BoxLayout* box_layout_;
   SpecialPopupRow* title_row_;
   FixedSizedScrollView* scroller_;
   views::View* scroll_content_;
   views::ProgressBar* progress_bar_;
 
   ScrollBorder* scroll_border_;  // Weak reference
 
   // The back button that appears in the material design title row. Not owned.
   views::Button* back_button_;
 
+  // Used to delay the transition to the default view.
+  std::unique_ptr<base::OneShotTimer> transition_delay_timer_;
+
   DISALLOW_COPY_AND_ASSIGN(TrayDetailsView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_TRAY_DETAILS_VIEW_H_