Add a gpu_unittests isolate.

Add a gpu_unittests isolate.

The goal is to run gpu_unittests on the GPU bots, starting with the
FYI bots.

BUG=391895
Committed: https://crrev.com/5ffe286fbe472df7789a1cb61035652fddeb6113
Cr-Commit-Position: refs/heads/master@{#294268}

[Jamie Madill, 2014-09-10 18:54:49]

jmadill@chromium.org changed reviewers:
+ csharp@chromium.org

[Jamie Madill, 2014-09-10 18:57:11]

PTAL... tested the isolate on Windows and Linux. Not sure why the new isolate is
marked as "A+" with a diff (the file is based on content_gl_tests as Ken
suggested)

[csharp, 2014-09-10 20:57:38]

lgtm

[Ken Russell (switch to Gerrit), 2014-09-10 22:46:52]

kbr@chromium.org changed reviewers:
+ kbr@chromium.org

[Ken Russell (switch to Gerrit), 2014-09-10 22:46:53]

LGTM too.

Git, I think, is treating the new file as an addition + modifications because of
the similarity to another file in the source tree.

[Jamie Madill, 2014-09-10 22:57:25]

The CQ bit was checked by jmadill@chromium.org

[commit-bot: I haz the power, 2014-09-10 23:18:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/562733003/1

[commit-bot: I haz the power, 2014-09-11 00:13:25]

Committed patchset #1 (id:1) as 35e13f9587238144b756c107003a5721d915805d

[commit-bot: I haz the power, 2014-09-11 00:19:12]

Patchset 1 (id:??) landed as
https://crrev.com/5ffe286fbe472df7789a1cb61035652fddeb6113
Cr-Commit-Position: refs/heads/master@{#294268}