Add landmine due to generated file move in Blink r175513

Add landmine due to generated file move in Blink r175513

Blink generated file move requires a clobber to avoid using stale
generated files.

This should have been included in the Blink roll, but we
didn't realize this was needed, so we failed to advise the
gardener (sorry!):
Blink roll 175512:175568
https://codereview.chromium.org/317183002/

See discussion at:
https://code.google.com/p/chromium/issues/detail?id=381111#c4

BUG=381111
TBR=dcheng
TBR=peter

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=275406

[Nils Barth (inactive), 2014-06-06 03:06:12]

Adding a landmine to clobber build to resolve build failures; looks ok?

[Nils Barth (inactive), 2014-06-06 03:06:15]

The CQ bit was checked by nbarth@chromium.org

[commit-bot: I haz the power, 2014-06-06 03:08:44]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/nbarth@chromium.org/316343003/1

[haraken, 2014-06-06 03:10:29]

LGTM

[Nils Barth (inactive), 2014-06-06 03:15:46]

The CQ bit was unchecked by nbarth@chromium.org

[Nils Barth (inactive), 2014-06-06 03:15:50]

The CQ bit was checked by nbarth@chromium.org

[commit-bot: I haz the power, 2014-06-06 03:16:17]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/nbarth@chromium.org/316343003/1

[commit-bot: I haz the power, 2014-06-06 08:06:49]

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

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

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

[commit-bot: I haz the power, 2014-06-06 09:09:11]

Try jobs failed on following builders:
  linux_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_rel/bu...)

[Nils Barth (inactive), 2014-06-06 09:22:14]

The CQ bit was checked by nbarth@chromium.org

[commit-bot: I haz the power, 2014-06-06 09:23:47]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/nbarth@chromium.org/316343003/1

[commit-bot: I haz the power, 2014-06-06 11:25:21]

Change committed as 275406