Add MenuItemView API to add and remove items at a particular index.

views/controls/menu/menu_controller.cc

Index: views/controls/menu/menu_controller.cc
diff --git a/views/controls/menu/menu_controller.cc b/views/controls/menu/menu_controller.cc
index 5703d693e99db415b750686263a2655ab3fade1f..eee5f9ff23791bc4e9117d5310513a6dfb48d619 100644
--- a/views/controls/menu/menu_controller.cc
+++ b/views/controls/menu/menu_controller.cc
@@ -1344,14 +1344,11 @@ void MenuController::MenuChildrenChanged(MenuItemView* item) {
   DCHECK(item);
   DCHECK(item->GetSubmenu()->IsShowing());
 
-  // Currently this only supports adjusting the bounds of the last menu.
-  DCHECK(item == state_.item->GetParentMenuItem());
-
   // Make sure the submenu isn't showing for the current item (the position may
   // have changed or the menu removed). This also moves the selection back to
   // the parent, which handles the case where the selected item was removed.
-  SetSelection(state_.item->GetParentMenuItem(),
-               SELECTION_OPEN_SUBMENU | SELECTION_UPDATE_IMMEDIATELY);
+  if (state_.item)
+    SetSelection(item, SELECTION_OPEN_SUBMENU | SELECTION_UPDATE_IMMEDIATELY);

[sky, 2011/05/06 16:17:00]

This isn't right. It forces the selection to be what changed. What if item
wasn't even open?

[rhashimoto, 2011/05/11 00:44:53]

You're right.  I've changed this to check if the changed item is an ancestor of
the selection (or *is* the selection).  If yes, then the selection is moved to
the changed item and repositioned.  Otherwise nothing is done.

 
   OpenMenuImpl(item, false);
 }