Store all items and submenus value based in ContextMenu and ContextMenuItem.
That fixes the crashes when the context menu was populated with sub-menus because
of the use of temporary ContextMenu objects like this:

ContextMenu subMenu(...);
subMenu.appendItem(...);
subMenu.appendItem(...);

subMenuItem.setSubMenu(&subMenu); // temporary pointer, need to _copy_ contents

Signed-off-by: Holger


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@27644 268f45cc-cd09-0410-ab3c-d52691b4dbfc