Do not trigger compositing update on selection gap update for SPv2

Do not trigger compositing update on selection gap update for SPv2

Doing so results in assertion failure because the document lifecycle does not
allow rewinding from InPaintForSlimmingPaintV2 back to LayoutClean.

Skipping compositing update should be fine since SPv2 doesn't rely on old world
compositing anyway.

BUG=524879
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201244

[trchen, 2015-08-26 05:16:41]

trchen@chromium.org changed reviewers:
+ chrishtr@chromium.org, wkorman@chromium.org

[trchen, 2015-08-26 05:16:47]

The CQ bit was checked by trchen@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-08-26 05:16:52]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1312363003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1312363003/1

[commit-bot: I haz the power, 2015-08-26 06:41:00]

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

[commit-bot: I haz the power, 2015-08-26 06:41:00]

Dry run: This issue passed the CQ dry run.

[wkorman, 2015-08-26 17:51:53]

lgtm

[chrishtr, 2015-08-26 18:26:45]

lgtm

[trchen, 2015-08-26 20:09:55]

The CQ bit was checked by trchen@chromium.org

[commit-bot: I haz the power, 2015-08-26 20:10:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1312363003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1312363003/1

[commit-bot: I haz the power, 2015-08-26 20:16:47]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201244