aura: Add flag to indicate if a drag session is started with touch or mouse.

ui/views/controls/menu/menu_controller.cc

Index: ui/views/controls/menu/menu_controller.cc
diff --git a/ui/views/controls/menu/menu_controller.cc b/ui/views/controls/menu/menu_controller.cc
index 2bba4026b2f39ce87af51d03d097bde9d2bd1d6a..3b3758a36e8de1a567d261c0808c9f50dab05ad9 100644
--- a/ui/views/controls/menu/menu_controller.cc
+++ b/ui/views/controls/menu/menu_controller.cc
@@ -863,7 +863,8 @@ void MenuController::StartDrag(SubmenuView* source,
   StopScrolling();
   int drag_ops = item->GetDelegate()->GetDragOperations(item);
   drag_in_progress_ = true;
-  item->GetWidget()->RunShellDrag(NULL, data, widget_loc, drag_ops);
+  item->GetWidget()->RunShellDrag(NULL, data, widget_loc, drag_ops,
+      ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE);

[sky, 2012/11/05 18:13:56]

Don't we use this path for touch dragging too? I suspect on windows we could hit
this for touch.

[varunjain, 2012/11/05 18:25:49]

Even if we do, this should not change the behavior as it currently is. I have
followup CL(s) to properly enable touch dragging which will use this flag. I
will update this value accordingly in those CLs.

   drag_in_progress_ = false;
 
   if (GetActiveInstance() == this) {