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

ash/common/system/tray/system_tray_item.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_SYSTEM_TRAY_ITEM_H_
 #define ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 
+#include <memory>
+
 #include "ash/ash_export.h"
 #include "ash/common/login_status.h"
 #include "ash/public/cpp/shelf_types.h"
 #include "base/macros.h"
 
+namespace base {
+class OneShotTimer;
+}  // namespace base
+
 namespace views {
 class View;
 }
 
 namespace ash {
 class SystemTray;
 class SystemTrayBubble;
 class TrayItemView;
 
 class ASH_EXPORT SystemTrayItem {
@@ skipping 75 matching lines @@
   virtual void UpdateAfterLoginStatusChange(LoginStatus status);
 
   // Updates the tray view (if applicable) when shelf's alignment changes.
   // The default implementation does nothing.
   virtual void UpdateAfterShelfAlignmentChange(ShelfAlignment alignment);
 
   // Shows the detailed view for this item. If the main popup for the tray is
   // currently visible, then making this call would use the existing window to
   // display the detailed item. The detailed item will inherit the bounds of the
   // existing window.
-  // If there is no existing view, then this is equivalent to calling
-  // PopupDetailedView(0, true).
+  //
+  // In Material Design the actual transition is intentionally delayed to allow
+  // the user to perceive the ink drop animation on the clicked target.
   void TransitionDetailedView();
 
   // Pops up the detailed view for this item. An item can request to show its
   // detailed view using this function (e.g. from an observer callback when
   // something, e.g. volume, network availability etc. changes). If
   // |for_seconds| is non-zero, then the popup is closed after the specified
   // time.
   void PopupDetailedView(int for_seconds, bool activate);
 
   // Continue showing the currently-shown detailed view, if any, for
@@ skipping 15 matching lines @@
   // the shelf is in the auto-hide state. Default is true.
   virtual bool ShouldShowShelf() const;
 
   // Returns the system tray that this item belongs to.
   SystemTray* system_tray() const { return system_tray_; }
 
   bool restore_focus() const { return restore_focus_; }
   void set_restore_focus(bool restore_focus) { restore_focus_ = restore_focus; }
 
  private:
+  // Actually transitions to the detailed view.
+  void DoTransitionToDetailedView();
+
   // Accesses uma_type().
   friend class SystemTrayBubble;
 
   UmaType uma_type() const { return uma_type_; }
 
   SystemTray* system_tray_;
   UmaType uma_type_;
   bool restore_focus_;
 
+  // Used to delay the transition to the detailed view.
+  std::unique_ptr<base::OneShotTimer> transition_delay_timer_;
+
   DISALLOW_COPY_AND_ASSIGN(SystemTrayItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_