This reduces the jank when scrolling down in top-level Settings if you happen to have several account types like Google, Twitter, Facebook, etc. In the process of doing this, discovered that headers get built even when they're not showing (SubSettings). Skip setting up the headers, which can be expensive when there are several accounts. Bug: 11006601 Change-Id: I8b4eafdcc2fc2beecac01317c3c8f07a82febcc0