Move variations component code to variations namespace.

Move variations component code to variations namespace.

This is a re-land of https://codereview.chromium.org/412943002/
which broke on the official builder.

BUG=284540
TBR=sky@chromium.org, mathp@chromium.org, jwd@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=285778

[Alexei Svitkine (slow), 2014-07-25 21:30:52]

The CQ bit was checked by asvitkine@chromium.org

[commit-bot: I haz the power, 2014-07-25 21:33:39]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/asvitkine@chromium.org/421663003/20001

[commit-bot: I haz the power, 2014-07-25 23:32:28]

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

[commit-bot: I haz the power, 2014-07-25 23:45:03]

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

[commit-bot: I haz the power, 2014-07-25 23:45:04]

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

[Alexei Svitkine (slow), 2014-07-26 02:51:32]

The CQ bit was checked by asvitkine@chromium.org

[commit-bot: I haz the power, 2014-07-26 05:00:18]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/asvitkine@chromium.org/421663003/20001

[commit-bot: I haz the power, 2014-07-26 18:35:51]

Change committed as 285778