Add settings:: namespace to MdSettingsUi.

Move MdSettingsUi to its own directory. There will be additional settings-related files in the near future, so this directory will be used to organize them.

BUG=

Committed: https://crrev.com/150f086c1cc91090378a61556d58b70fd53dc32d
Cr-Commit-Position: refs/heads/master@{#322279}

[Kyle Horimoto, 2015-03-25 22:17:08]

khorimoto@chromium.org changed reviewers:
+ jlklein@chromium.org

[Kyle Horimoto, 2015-03-25 22:24:36]

khorimoto@chromium.org changed reviewers:
+ jhawkins@chromium.org

[James Hawkins, 2015-03-25 22:26:58]

Why is this necessary?

[Kyle Horimoto, 2015-03-25 22:30:16]

On 2015/03/25 22:26:58, James Hawkins wrote:
> Why is this necessary?

It helps to organize our settings-related code by associating it with a
namespace. I'm working on adding a utility function to add localized strings to
our page's WebUiDataSource, and I'd like that function and this class to be
namespaced instead of just adding a AddLocalizedSettingsStrings() function to
the global namespace.

[James Hawkins, 2015-03-25 22:42:55]

If we're going to be adding more files (which it sounds like we are), then we
need to create a ui/webui/settings directory.  If we have that, I don't see the
benefit of namespacing with settings.

[Kyle Horimoto, 2015-03-25 23:04:50]

On 2015/03/25 22:42:55, James Hawkins wrote:
> If we're going to be adding more files (which it sounds like we are), then we
> need to create a ui/webui/settings directory.  If we have that, I don't see
the
> benefit of namespacing with settings.

Added new directory and removed the namespace.

[James Hawkins, 2015-03-25 23:07:14]

lgtm

[Kyle Horimoto, 2015-03-25 23:24:21]

The CQ bit was checked by khorimoto@chromium.org

[Kyle Horimoto, 2015-03-25 23:24:21]

The patchset sent to the CQ was uploaded after l-g-t-m from
jhawkins@chromium.org
Link to the patchset: https://codereview.chromium.org/1015533019/#ps50001
(title: "Builds successfully.")

[commit-bot: I haz the power, 2015-03-25 23:25:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1015533019/50001

[commit-bot: I haz the power, 2015-03-26 00:47:12]

Committed patchset #4 (id:50001)

[commit-bot: I haz the power, 2015-03-26 00:47:53]

Patchset 4 (id:??) landed as
https://crrev.com/150f086c1cc91090378a61556d58b70fd53dc32d
Cr-Commit-Position: refs/heads/master@{#322279}