[New Multicolumn] Create a virtual testsuite for the region based multicol impl.

[New Multicolumn] Create a virtual testsuite for the region based multicol impl.

It is currently possible to switch between the old and the new multicol
implementation though Javascript. This means that individual tests may
"choose" in which implementation they should be evaluated. We wish to
remove the use of this Javascript toggle where it's not necessary
(ultimately everywhere), and use virtual test suites instead---even in the
transitional period where both implementations exist.

This patch is the first in a series which aims to fix this.

The virtual/regionbasedmulticol suite tests everything in fast/multicol,
except the tests which fail because the baseline is based on the old
implementation of multicol. The skipped tests should later be evaluated
individually, and baselined in the virtual/regionbasedmulticol suite, if
applicable.

I have verified that all the tests we skip in the virtual test suite use
the old multicol implementation.

Note: The tests fast/multicol/mixed-opacity-test.html and
multicol/mixed-opacity-fixed-test.html are "new" tests which fail due to a
known bug.

BUG=334335
R=rune@opera.com

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177488

[rune, 2014-06-20 12:31:49]

lgtm

you should add a BUG= pointing to the main issue for the multicol rewrite, or
add a blocker bug for these changes if you wish.

you might need a separate lgtm for Tools/

[Julien - ping for review, 2014-06-30 21:24:03]

lgtm

[Julien - ping for review, 2014-06-30 21:31:22]

+Dirk, Tools/OWNERs needed for a new virtual test suite.

[Dirk Pranke, 2014-06-30 22:02:45]

lgtm

[andersr, 2014-07-01 07:29:40]

The CQ bit was checked by andersr@opera.com

[commit-bot: I haz the power, 2014-07-01 07:30:22]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/andersr@opera.com/343963002/20001

[commit-bot: I haz the power, 2014-07-01 08:36:08]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/14782)

[commit-bot: I haz the power, 2014-07-01 09:44:11]

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

[commit-bot: I haz the power, 2014-07-01 09:44:12]

Try jobs failed on following builders:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)

[andersr, 2014-07-03 09:41:12]

The CQ bit was checked by andersr@opera.com

[commit-bot: I haz the power, 2014-07-03 09:41:43]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/andersr@opera.com/343963002/40001

[commit-bot: I haz the power, 2014-07-03 11:04:09]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/14102)

[commit-bot: I haz the power, 2014-07-03 11:42:49]

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

[commit-bot: I haz the power, 2014-07-03 11:42:49]

Try jobs failed on following builders:
  mac_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/14108)

[andersr, 2014-07-03 18:21:20]

The CQ bit was checked by andersr@opera.com

[commit-bot: I haz the power, 2014-07-03 18:22:30]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/andersr@opera.com/343963002/60001

[commit-bot: I haz the power, 2014-07-03 19:26:37]

Change committed as 177488

[Jason Robbins -- corp, 2014-09-11 20:28:03]

jrobbins@google.com changed reviewers:
- dpranke@chromioum.org