IPC: defend against excessive number of submenu entries in PPAPI message.

BUG=168710
Review URL: https://codereview.chromium.org/11794037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175576 0039d316-1c4b-4281-b951-d872f2087c98
bool CheckMenuItem(int depth, const PP_Flash_MenuItem* item) {
  if (item->type == PP_FLASH_MENUITEM_TYPE_SUBMENU)
    return CheckMenu(depth, item->submenu);
  return true;
}

bool CheckMenuItem(int depth, const PP_Flash_MenuItem* item) {
  if (item->type == PP_FLASH_MENUITEM_TYPE_SUBMENU)
    return CheckMenu(depth, item->submenu);
  return true;
}
