Support touch scroll gestures in menus.

views/controls/menu/submenu_view.h

Index: views/controls/menu/submenu_view.h
diff --git a/views/controls/menu/submenu_view.h b/views/controls/menu/submenu_view.h
index e176ac97f2dfba5cc27e3626c4c8925539111acb..4aa31fa3584c1c295e3f1d41000ef01977d23b0d 100644
--- a/views/controls/menu/submenu_view.h
+++ b/views/controls/menu/submenu_view.h
@@ -10,6 +10,7 @@
 
 #include "views/controls/menu/menu_delegate.h"
 #include "views/view.h"
+#include "ui/views/animation/scroll_animator.h"
 
 namespace views {
 
@@ -32,7 +33,8 @@ class 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[];
@@ -73,6 +75,9 @@ class VIEWS_EXPORT SubmenuView : public View {
   // 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();
 
@@ -169,6 +174,9 @@ class VIEWS_EXPORT SubmenuView : public View {
   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_;
 
@@ -195,6 +203,9 @@ class VIEWS_EXPORT SubmenuView : public View {
   // 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);
 };