Refactor device/BUILD.gn to list source files only once.

Refactor device/BUILD.gn to list source files only once.

Updating device/BUILD.gn to follow GN style guide,
listing source and deps items only once guarded by
conditionals. (Not listing all, then removing some
based on conditions).
https://code.google.com/p/chromium/wiki/GNStyleGuide#Sources

Prepares BUILD.gn for additional sources/deps logic
expected to add android support for device_unittests.

BUG=471536
Committed: https://crrev.com/7a4cf04e2b9e2c3421cd7137afc39ec3c9e6eb46
Cr-Commit-Position: refs/heads/master@{#322978}

[scheib, 2015-03-30 22:43:29]

Patchset #1 (id:1) has been deleted

[scheib, 2015-03-30 22:50:46]

scheib@chromium.org changed reviewers:
+ reillyg@chromium.org

[Reilly Grant (use Gerrit), 2015-03-30 22:55:23]

lgtm

This looks much better. Thank you.

[scheib, 2015-03-31 04:30:01]

The CQ bit was checked by scheib@chromium.org

[scheib, 2015-03-31 04:30:01]

The patchset sent to the CQ was uploaded after l-g-t-m from reillyg@chromium.org
Link to the patchset: https://codereview.chromium.org/1045913003/#ps40001
(title: " ")

[commit-bot: I haz the power, 2015-03-31 04:30:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1045913003/40001

[commit-bot: I haz the power, 2015-03-31 04:33:53]

Committed patchset #2 (id:40001)

[commit-bot: I haz the power, 2015-03-31 04:34:21]

Patchset 2 (id:??) landed as
https://crrev.com/7a4cf04e2b9e2c3421cd7137afc39ec3c9e6eb46
Cr-Commit-Position: refs/heads/master@{#322978}