Simplify GetPyProtoPath.

Simplify GetPyProtoPath.

We shouldn't hard code out/Release (since with GN the path could be different) or look for the checkout directory (since with swarming it doesn't exist).

This was needed with ui_tests or pyauto, but not with the current browser_tests binaries.

BUG=463180
Committed: https://crrev.com/35e1c076cbda56bd384f1b409f1bd782bd0fb70d
Cr-Commit-Position: refs/heads/master@{#318892}

[jam, 2015-03-03 05:12:32]

Patchset #1 (id:1) has been deleted

[jam, 2015-03-03 06:19:41]

Patchset #2 (id:40001) has been deleted

[jam, 2015-03-03 06:33:48]

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

[jam, 2015-03-03 06:33:49]

Chris: the CrOS tryrun is green. I noticed that sync_integration_tests doesn't
run on the CrOS trybot (not sure if that's an oversight or its on purpose, but
that test suite doesn't run on any CrOS waterfall builders either) so I verified
it still passes locally with this change.

[Chris Masone, 2015-03-03 15:19:31]

I don't even remember writing this code, or what it was used for :-)

LGTM, I suppose.

[jam, 2015-03-03 15:28:17]

The CQ bit was checked by jam@chromium.org

[commit-bot: I haz the power, 2015-03-03 15:29:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/969313002/20001

[commit-bot: I haz the power, 2015-03-03 16:37:08]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2015-03-03 16:38:19]

Patchset 1 (id:??) landed as
https://crrev.com/35e1c076cbda56bd384f1b409f1bd782bd0fb70d
Cr-Commit-Position: refs/heads/master@{#318892}