Remove some unnecessary using namespaces and add include guards

Remove some unnecessary using namespaces and add include guards

The Chromium Code Style doesn't allow using namespace and when
I looked at the code it seems some of them in layout are not
even needed. This removes the ones that are not needed and
adds explicit scoping at the one place it's needed.

Also adding a missing header guard and remove an unused enum.

Review-Url: https://codereview.chromium.org/2722313007
Cr-Commit-Position: refs/heads/master@{#454563}
Committed: https://chromium.googlesource.com/chromium/src/+/a333b76c54e0058b23fa8f2ffb6a64dc53fbb6e1

[Daniel Bratell, 2017-03-02 17:26:10]

bratell@opera.com changed reviewers:
+ fs@opera.com

[Daniel Bratell, 2017-03-02 17:26:10]

fs, similar to the changes in the html folder.

[fs, 2017-03-02 18:14:56]

lgtm

[Daniel Bratell, 2017-03-03 09:39:13]

The CQ bit was checked by bratell@opera.com

[commit-bot: I haz the power, 2017-03-03 09:39:24]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-03 11:10:16]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1488533953209780, "parent_rev":
"80982375344ea433398563da77ed793db949003a", "commit_rev":
"a333b76c54e0058b23fa8f2ffb6a64dc53fbb6e1"}

[commit-bot: I haz the power, 2017-03-03 11:10:54]

Description was changed from

==========
Remove some unnecessary using namespaces and add include guards

The Chromium Code Style doesn't allow using namespace and when
I looked at the code it seems some of them in layout are not
even needed. This removes the ones that are not needed and
adds explicit scoping at the one place it's needed.

Also adding a missing header guard and remove an unused enum.
==========

to

==========
Remove some unnecessary using namespaces and add include guards

The Chromium Code Style doesn't allow using namespace and when
I looked at the code it seems some of them in layout are not
even needed. This removes the ones that are not needed and
adds explicit scoping at the one place it's needed.

Also adding a missing header guard and remove an unused enum.

Review-Url: https://codereview.chromium.org/2722313007
Cr-Commit-Position: refs/heads/master@{#454563}
Committed:
https://chromium.googlesource.com/chromium/src/+/a333b76c54e0058b23fa8f2ffb6a...
==========

[commit-bot: I haz the power, 2017-03-03 11:10:55]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/a333b76c54e0058b23fa8f2ffb6a...