GN: Remove content/app -> mojo/application_manager dep

GN: Remove content/app -> mojo/application_manager dep

This dependency doesn't exist in the gyp build and doesn't appear to be
used.

Committed: https://crrev.com/5c8274db40827d96b66493ac513b888cba152997
Cr-Commit-Position: refs/heads/master@{#301666}

[jamesr, 2014-10-28 06:17:13]

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

[jam, 2014-10-28 17:12:49]

lgtm

[jamesr, 2014-10-28 17:41:08]

The CQ bit was checked by jamesr@chromium.org

[commit-bot: I haz the power, 2014-10-28 17:41:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/681213002/1

[commit-bot: I haz the power, 2014-10-28 18:28:26]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-28 18:29:13]

Patchset 1 (id:??) landed as
https://crrev.com/5c8274db40827d96b66493ac513b888cba152997
Cr-Commit-Position: refs/heads/master@{#301666}