Support touch scroll gestures in menus.

ui/views/controls/menu/submenu_view.h

 // Copyright (c) 2011 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 UI_VIEWS_CONTROLS_MENU_SUBMENU_VIEW_H_
 #define UI_VIEWS_CONTROLS_MENU_SUBMENU_VIEW_H_
 #pragma once
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "ui/views/controls/menu/menu_delegate.h"
 #include "ui/views/view.h"
+#include "ui/views/animation/scroll_animator.h"
 
 namespace views {
 
 class MenuHost;
 class MenuItemView;
 class MenuScrollViewContainer;
 
 // SubmenuView is the parent of all menu items.
 //
 // SubmenuView has the following responsibilities:
 // . It positions and sizes all child views (any type of View may be added,
 //   not just MenuItemViews).
 // . Forwards the appropriate events to the MenuController. This allows the
 //   MenuController to update the selection as the user moves the mouse around.
 // . Renders the drop indicator during a drop operation.
 // . Shows and hides the window (a NativeWidgetWin) when the menu is shown on
 //   screen.
 //
 // SubmenuView is itself contained in a MenuScrollViewContainer.
 // MenuScrollViewContainer handles showing as much of the SubmenuView as the
 // screen allows. If the SubmenuView is taller than the screen, scroll buttons
 // are provided that allow the user to see all the menu items.
-class VIEWS_EXPORT SubmenuView : public View {
+class VIEWS_EXPORT SubmenuView : public View,
+                                 public ScrollDelegate {
  public:
   // The submenu's class name.
   static const char kViewClassName[];
 
   // Creates a SubmenuView for the specified menu item.
   explicit SubmenuView(MenuItemView* parent);
   virtual ~SubmenuView();
 
   // Returns the number of child views that are MenuItemViews.
   // MenuItemViews are identified by ID.
@@ skipping 20 matching lines @@
   virtual bool AreDropTypesRequired() OVERRIDE;
   virtual bool CanDrop(const OSExchangeData& data) OVERRIDE;
   virtual void OnDragEntered(const DropTargetEvent& event) OVERRIDE;
   virtual int OnDragUpdated(const DropTargetEvent& event) OVERRIDE;
   virtual void OnDragExited() OVERRIDE;
   virtual int OnPerformDrop(const DropTargetEvent& event) OVERRIDE;
 
   // Scrolls on menu item boundaries.
   virtual bool OnMouseWheel(const MouseWheelEvent& e) OVERRIDE;
 
+  // Scrolls on menu item boundaries.
+  virtual ui::GestureStatus OnGestureEvent(const GestureEvent& e) OVERRIDE;
+
   // Returns true if the menu is showing.
   bool IsShowing();
 
   // Shows the menu at the specified location. Coordinates are in screen
   // coordinates. max_width gives the max width the view should be.
   void ShowAt(Widget* parent,
               const gfx::Rect& bounds,
               bool do_capture);
 
   // Resets the bounds of the submenu to |bounds|.
@@ skipping 76 matching lines @@
                           MenuItemView* item,
                           MenuDelegate::DropPosition position);
 
   void SchedulePaintForDropIndicator(MenuItemView* item,
                                      MenuDelegate::DropPosition position);
 
   // Calculates the location of th edrop indicator.
   gfx::Rect CalculateDropIndicatorBounds(MenuItemView* item,
                                          MenuDelegate::DropPosition position);
 
+  // Implementation of ScrollDelegate
+  virtual void OnScroll(float dx, float dy) OVERRIDE;
+
   // Parent menu item.
   MenuItemView* parent_menu_item_;
 
   // Widget subclass used to show the children. This is deleted when we invoke
   // |DestroyMenuHost|, or |MenuHostDestroyed| is invoked back on us.
   MenuHost* host_;
 
   // If non-null, indicates a drop is in progress and drop_item is the item
   // the drop is over.
   MenuItemView* drop_item_;
 
   // Position of the drop.
   MenuDelegate::DropPosition drop_position_;
 
   // Ancestor of the SubmenuView, lazily created.
   MenuScrollViewContainer* scroll_view_container_;
 
   // See description above getter.
   int max_accelerator_width_;
 
   // Minimum width returned in GetPreferredSize().
   int minimum_preferred_width_;
 
   // Reposition open menu when contained views change size.
   bool resize_open_menu_;
 
+  // The submenu's scroll animator
+  scoped_ptr<ScrollAnimator> scroll_animator_;
+
   DISALLOW_COPY_AND_ASSIGN(SubmenuView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_MENU_SUBMENU_VIEW_H_