Reland "Recompute overflow after transform changes"

Reland "Recompute overflow after transform changes"

This CL adds a special code path that is very similar to simplifiedLayout.
When the only change on an element is the transform, we can do the minimal
work to recompute the layout overflow without much overhead from layout.

This is done by adding an overflow recalculation phase after style changes,
if a RenderObject doesn't need layout and has moved transformed children,
the special code path will kick in.

BUG=352460
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=172833

[trchen, 2014-04-25 02:40:39]

This should be ready for trybots by the time
https://codereview.chromium.org/255433003/ lands.

[ojan, 2014-04-25 04:35:05]

lgtm

[trchen, 2014-04-29 00:34:02]

The CQ bit was checked by trchen@chromium.org

[commit-bot: I haz the power, 2014-04-29 00:34:45]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/trchen@chromium.org/250773002/80001

[commit-bot: I haz the power, 2014-04-29 03:43:50]

Change committed as 172833