Remove several unneeded modules from webkitpy.common.

Remove several unneeded modules from webkitpy.common.

webkitpy.common.editdistance, webkitpy.common.lru_cache, and
webkitpy.common.thread were no longer being used.

webkitpy.common.newstringio could be (and should've been) replaced by
io.StringIO() or io.BytesIO() as appropriate to indicate if you were
dealing with text or bytes.

R=abarth@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180397

[abarth-chromium, 2014-08-15 18:17:25]

lgtm

[Dirk Pranke, 2014-08-15 20:35:35]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2014-08-15 20:36:13]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dpranke@chromium.org/479633002/1

[commit-bot: I haz the power, 2014-08-15 21:34:43]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/22989)
  mac_gpu_retina_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu_retina_tr...)
  mac_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu_triggered...)

[commit-bot: I haz the power, 2014-08-15 22:18:29]

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

[commit-bot: I haz the power, 2014-08-15 22:18:30]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/22998)

[Dirk Pranke, 2014-08-15 22:23:14]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2014-08-15 22:23:41]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dpranke@chromium.org/479633002/1

[commit-bot: I haz the power, 2014-08-15 23:32:14]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/23009)

[commit-bot: I haz the power, 2014-08-16 00:11:25]

Committed patchset #1 (1) as 180397