Windows perf bots: fixes android pylib initialization.

Windows perf bots: fixes android pylib initialization.

Following crrev.com/202558, android's pylib was initialized on platforms that didn't need.
Check for platform and also make it safer to use should there be problems with "which".

BUG=242960
R=tonyg@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=202669

[bulach, 2013-05-28 16:26:42]

sorry about the breakage.

[tonyg, 2013-05-28 16:47:26]

lgtm

[commit-bot: I haz the power, 2013-05-28 16:48:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/bulach@chromium.org/15804004/1

[ramant (doing other things), 2013-05-28 19:22:03]

On 2013/05/28 16:48:33, I haz the power (commit-bot) wrote:
> CQ is trying da patch. Follow status at
> https://chromium-status.appspot.com/cq/bulach%40chromium.org/15804004/1

Is it possible to manually commit this (if CQ is going to take long time)?
thanks

[commit-bot: I haz the power, 2013-05-28 20:25:46]

Retried try job too often on win_rel for step(s) chrome_frame_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[commit-bot: I haz the power, 2013-05-28 20:26:36]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/bulach@chromium.org/15804004/1

[Julien - ping for review, 2013-05-28 22:25:09]

Committed patchset #1 manually as r202669 (presubmit successful).

[bulach, 2013-05-29 09:27:30]

thanks all for landing this, apologies again for the breakage.