The point of GestureTapDown is to provide UI feedback to the user about what they're about to tap on (or already have tapped in some cases). However, if the page moves (or DOM changes) between TapDown and Tap, we will tap a different element than was highlighted to the user. Is this OK? Or perhaps we should do one of:
1) Save the target found for tap down, and re-use it for tap
2) Save the target found for tap down, and do another hit-test on tap but if it doesn't match, dispatch a TapCancel instead
See bug 96677 and http://code.google.com/p/chromium/issues/detail?id=132439 for some more discussion.
One solution for this is do suspend active DOM objects while the finger is down. This is what I believe the out-of-trunk iPhone and Android branches does, and what Qt does in trunk using Page::suspendActiveDOMObjectsAndAnimations.
This also has the benefit of smoother animations due to less things happening at the same time.
Haven't really seen issues from this, I don't think we ever did anything to address it in blink either.