Move TemplateURLService preferences registration to the component

Move TemplateURLService preferences registration to the component

Move the preferences registration to a static method of TemplateURLService
so that it can be shared by different embedders and call the method from
the factory.

BUG=371535
Committed: https://crrev.com/294879611d3d64e57d762a117413a2f14bed03ad
Cr-Commit-Position: refs/heads/master@{#337297}

[sdefresne, 2015-07-02 12:19:04]

sdefresne@chromium.org changed reviewers:
+ pkasting@chromium.org

[sdefresne, 2015-07-02 12:19:05]

Please take a look.

[Peter Kasting, 2015-07-03 09:05:05]

LGTM

[sdefresne, 2015-07-03 09:20:12]

The CQ bit was checked by sdefresne@chromium.org

[commit-bot: I haz the power, 2015-07-03 09:20:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1211083006/1

[commit-bot: I haz the power, 2015-07-03 09:24:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-03 09:26:41]

Patchset 1 (id:??) landed as
https://crrev.com/294879611d3d64e57d762a117413a2f14bed03ad
Cr-Commit-Position: refs/heads/master@{#337297}