Add command line switch to enable region based columns.

Add command line switch to enable region based columns.

This needs to be a separate switch - we cannot lump it together with
--enable-experimental-webkit-features , because we don't want
to unconditionally enable region based columns when running LayoutTests
(there are LayoutTests that compare rendering in the old and new multicol
implementations, using internals.settings.setRegionBasedColumnsEnabled(true)).

BUG=242905
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=207005

[Jói, 2013-06-17 19:04:49]

LGTM.  I reviewed the entire change, although I am not a good reviewer for the
//webkit bits.  Best to speicfy what you want each reviewer to look at when
specifying multiple reviewers.

Cheers,
Jói

[jamesr, 2013-06-17 19:31:34]

webkit/ lgtm

[commit-bot: I haz the power, 2013-06-18 08:20:31]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mstensho@opera.com/17057003/1

[commit-bot: I haz the power, 2013-06-18 08:37:48]

Retried try job too often on chromium_presubmit for step(s) presubmit
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=chromium_p...

[mstensho (USE GERRIT), 2013-06-18 08:47:55]

Oops, I'm new here. Sorry for the mess.
I went throught various OWNERS files, picked one reviewer for each directory
(chose randomly when there were multiple options), and ended up with this:

content/browser/: sky@chromium.org
content/public/: joi@chromium.org
webkit/: jamesr@chromium.org

It appears that I still need an LGTM from sky before I can commit.

[sky, 2013-06-18 13:46:33]

content/browser LGTM

[commit-bot: I haz the power, 2013-06-18 13:49:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mstensho@opera.com/17057003/1

[commit-bot: I haz the power, 2013-06-18 15:51:16]

Change committed as 207005