First checked-in import of the W3C's test suites.

First checked-in import of the W3C's test suites.

The test suites are moving from being pulled in via src/DEPS to
LayoutTests/w3c to being checked in directly to LayoutTests/imported.

This import uses update-w3c-deps run manually and
imported csswg-test@6ed3bb6642b0d382ce8c3f7912172f2420eb7756 and
imported web-platform-tests@6ed3bb6642b0d382ce8c3f7912172f2420eb7756

In addition, we modify run-webkit-tests to manually skip the old
LayoutTests/w3c directory if it exists, and to start printing warnings
that the repos are stale and should be deleted.

This is patchset 3 of the 4 needed to complete the cutover.

TBR=eseidel@chromium.org
BUG=413454
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181874

[Dirk Pranke, 2014-09-12 02:05:29]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2014-09-12 02:06:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/560893005/20001

[commit-bot: I haz the power, 2014-09-12 02:34:35]

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

[commit-bot: I haz the power, 2014-09-12 02:34:37]

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

[Dirk Pranke, 2014-09-12 03:43:35]

Committed patchset #3 (id:20001) manually as 181874 (presubmit successful).