Sort GN files under content

Sort GN files under content

For tools/sort_sources.py to be useful, existing GYP files
should be sorted.

BUG=456014
TEST=everything should build as before

Committed: https://crrev.com/7fa9d30aaac588e4576f72aeb7d1f275f48b56e2
Cr-Commit-Position: refs/heads/master@{#316415}

[satorux1, 2015-02-13 07:06:47]

satorux@chromium.org changed reviewers:
+ jam@chromium.org

[satorux1, 2015-02-13 07:06:48]

PTAL

[jam, 2015-02-13 16:54:57]

lgtm

[satorux1, 2015-02-16 00:20:46]

New patchsets have been uploaded after l-g-t-m from jam@chromium.org

[satorux1, 2015-02-16 00:41:16]

The CQ bit was checked by satorux@chromium.org

[commit-bot: I haz the power, 2015-02-16 00:42:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/922983002/20001

[commit-bot: I haz the power, 2015-02-16 00:45:01]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-16 00:45:50]

Patchset 2 (id:??) landed as
https://crrev.com/7fa9d30aaac588e4576f72aeb7d1f275f48b56e2
Cr-Commit-Position: refs/heads/master@{#316415}