HeaderFooterLayout: Port from timers to dirty/polish paradigm
timers in layouts? wut?
- The original initialization problem should probably be fixed with this patch in a different way: by delaying any layout operations until the componentComplete hook.
- After the componentComplete, everything else is delayed until the next polish event.
- A special boolean field acts as a safeguard against recursion. A new method is introduced to forcefully update layout without waiting for polish event.
- Tests have been adjusted to drop or replace unnecessary and incorrect waitForRendering calls with waitForItemPolished checks.