Add user_prefs and visitedlink components to GN build.

Add user_prefs and visitedlink components to GN build.

This doesn't hook up visitedlink_renderer since it depends on blink.

BUG=
R=jamesr@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=278404

[jamesr, 2014-06-19 00:08:28]

lgtm

[brettw, 2014-06-19 05:03:19]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2014-06-19 05:05:09]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/brettw@chromium.org/340953004/1

[commit-bot: I haz the power, 2014-06-19 13:06:42]

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

[commit-bot: I haz the power, 2014-06-19 13:06:43]

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

[brettw, 2014-06-19 16:52:32]

Committed patchset #1 manually as r278404.