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..b8753f572ff91ae83f9d094f732c4b5e0e462550 100644
--- a/ui/views/controls/menu/menu_host_root_view.cc
+++ b/ui/views/controls/menu/menu_host_root_view.cc
@@ -62,6 +62,19 @@ bool MenuHostRootView::OnMouseWheel(const MouseWheelEvent& event) {
 #endif
 }
 
+ui::GestureStatus MenuHostRootView::OnGestureEvent(const GestureEvent& event) {
+#if defined(OS_LINUX)

[sadrul, 2012/01/19 15:29:29]

Why is this ifdef necessary? My understanding is once we already have a
views::GestureEvent, the event processing from thereon should be fine on all
platforms?

+  // ChromeOS uses MenuController to forward events like other
+  // mouse events.
+  if (!GetMenuController())
+    return ui::GESTURE_STATUS_UNKNOWN;
+  return GetMenuController()->OnGestureEvent(submenu_, event);
+#else
+  // TODO(vollick): gestures in Windows.
+  return RootView::OnGestureEvent(event);
+#endif
+}
+
 MenuController* MenuHostRootView::GetMenuController() {
   return submenu_ ? submenu_->GetMenuItem()->GetMenuController() : NULL;
 }