Add "--test-type=gpu" to suppress API Keys InfoBar

Currently, when running tests on the GPU bots, we occasionally have
flakiness due to the presence (and subsequent hiding) of the "Google
API keys are missing" bar that appears at the top of the window when a
test starts (see crbug.com/533181).

This change adds the "test-type" flag, which suppresses this InfoBar,
among other things. Initial testing indicates that the other
side-effects to not interfere with GPU tests.

BUG=537776
Committed: https://crrev.com/cf5399db86adcbd97f5a2c7044cedc6747aaac49
Cr-Commit-Position: refs/heads/master@{#352443}

[Ken Russell (switch to Gerrit), 2015-10-05 20:29:40]

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

[Ken Russell (switch to Gerrit), 2015-10-05 20:29:40]

lgtm

Thanks for investigating this.

Could you add a comment in the various source files indicating that the
--test-type argument is mainly for suppressing this infobar?

Could you update the description of crbug.com/537776 describing the change of
direction, comment on that bug, and reference it from here?

Thanks.

[ericrk, 2015-10-05 20:45:47]

On 2015/10/05 at 20:29:40, kbr wrote:
> lgtm
> 
> Thanks for investigating this.
> 
> Could you add a comment in the various source files indicating that the
--test-type argument is mainly for suppressing this infobar?
> 
> Could you update the description of crbug.com/537776 describing the change of
direction, comment on that bug, and reference it from here?
> 
> Thanks.

Done. Thanks!

[Ken Russell (switch to Gerrit), 2015-10-05 20:50:15]

lgtm again. Thanks for taking care of this.

[ericrk, 2015-10-05 21:44:19]

The CQ bit was checked by ericrk@chromium.org

[commit-bot: I haz the power, 2015-10-05 21:45:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1384823002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1384823002/20001

[commit-bot: I haz the power, 2015-10-05 22:21:15]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-05 22:22:11]

Patchset 2 (id:??) landed as
https://crrev.com/cf5399db86adcbd97f5a2c7044cedc6747aaac49
Cr-Commit-Position: refs/heads/master@{#352443}