Support touch scroll gestures in menus.

ui/views/controls/menu/menu_host_root_view.cc

Index: ui/views/controls/menu/menu_host_root_view.cc
diff --git a/ui/views/controls/menu/menu_host_root_view.cc b/ui/views/controls/menu/menu_host_root_view.cc
index 44ed97f0ba8e9b842d6042cfa3c96966f3fa89e3..d75ad524585046fb3dae25f21ba754578eded080 100644
--- a/ui/views/controls/menu/menu_host_root_view.cc
+++ b/ui/views/controls/menu/menu_host_root_view.cc
@@ -62,6 +62,14 @@ bool MenuHostRootView::OnMouseWheel(const MouseWheelEvent& event) {
 #endif
 }
 
+ui::GestureStatus MenuHostRootView::OnGestureEvent(const GestureEvent& event) {
+  // ChromeOS uses MenuController to forward events like other
+  // mouse events.
+  if (!GetMenuController())
+    return ui::GESTURE_STATUS_UNKNOWN;
+  return GetMenuController()->OnGestureEvent(submenu_, event);
+}
+
 MenuController* MenuHostRootView::GetMenuController() {
   return submenu_ ? submenu_->GetMenuItem()->GetMenuController() : NULL;
 }