Fix pixel snapping of clipLayers and their descendants

Fix pixel snapping of clipLayers and their descendants

Hopefully the last in a line of compositing sub-pixel
patches. This correctly pixel snaps the clipping layer
used by composited layers with overflow: clip and
accumulates it into their children.

BUG=347521
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169624

[leviw_travelin_and_unemployed, 2014-03-20 01:08:23]

Last of the sub-pixel compositing bugs for awhile (I hope!!)

[eae, 2014-03-20 01:10:09]

LGTM

[eae, 2014-03-20 01:10:12]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-03-20 01:10:15]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/leviw@chromium.org/205213006/1

[commit-bot: I haz the power, 2014-03-20 02:05:32]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-20 02:05:32]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_dbg

[leviw_travelin_and_unemployed, 2014-03-20 02:32:03]

The CQ bit was checked by leviw@chromium.org

[commit-bot: I haz the power, 2014-03-20 02:32:04]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/leviw@chromium.org/205213006/1

[commit-bot: I haz the power, 2014-03-20 03:41:25]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-20 03:41:25]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_dbg

[leviw_travelin_and_unemployed, 2014-03-20 03:45:19]

The CQ bit was checked by leviw@chromium.org

[commit-bot: I haz the power, 2014-03-20 03:45:24]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/leviw@chromium.org/205213006/1

[commit-bot: I haz the power, 2014-03-20 04:59:37]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-20 04:59:38]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_dbg

[leviw_travelin_and_unemployed, 2014-03-20 05:16:58]

The CQ bit was checked by leviw@chromium.org

[commit-bot: I haz the power, 2014-03-20 05:16:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/leviw@chromium.org/205213006/1

[commit-bot: I haz the power, 2014-03-20 06:20:59]

Change committed as 169624