Block selection gaps are not invalidated

Block selection gaps are not invalidated

https://codereview.chromium.org/620553009 moved
the selection to invalidate-after-compositing-updates,
except that it lied and we still do some invalidations
on the spot. This is needed as we don't store the old
selection information so we can't generate the old
selection invalidation rect later.

This change just generates the invalidation on the spot
for block selection gaps (like we do for normal selection).

The long-term fix will be to store the old rect but it requires
more thoughts and we need some quick fix for this nasty issue.

BUG=421380
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=183890

[Julien - ping for review, 2014-10-16 19:19:18]

jchaffraix@chromium.org changed reviewers:
+ dsinclair@chromium.org, leviw@chromium.org, wangxianzhu@chromium.org

[Julien - ping for review, 2014-10-16 19:19:19]

Not super happy about this fix but we need to fix the selection regressions.

[Xianzhu, 2014-10-16 20:42:34]

lgtm for fixing the regression.

[Julien - ping for review, 2014-10-16 21:07:35]

The CQ bit was checked by jchaffraix@chromium.org

[commit-bot: I haz the power, 2014-10-16 21:07:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/659983002/1

[commit-bot: I haz the power, 2014-10-17 03:54:34]

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

[commit-bot: I haz the power, 2014-10-17 03:54:35]

Try jobs failed on following builders:
  mac_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/27307)

[Julien - ping for review, 2014-10-17 13:28:00]

The CQ bit was checked by jchaffraix@chromium.org

[commit-bot: I haz the power, 2014-10-17 13:28:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/659983002/20001

[commit-bot: I haz the power, 2014-10-17 14:50:23]

Committed patchset #2 (id:20001) as 183890