Report apptest_runner device not found infra failures.

Report apptest_runner device not found infra failures.

Make AndroidShell.InitShell return an exit code.
(infra exit code for infra errors and 'device not found')

Inline CleanShell in InitShell; store --origin internally.
Move gdb port forwarding to StartShell; minor refactoring.

BUG=493900
TEST=Mojo/Mandoline python scripts work as expected. Bots yield purple builds on "device not found" errors.
R=sky@chromium.org

Committed: https://crrev.com/ecce673617583e7f020518791b97dca6eeccef9e
Cr-Commit-Position: refs/heads/master@{#333186}

[msw, 2015-06-05 23:04:44]

Patchset #3 (id:40001) has been deleted

[msw, 2015-06-05 23:04:49]

Patchset #3 (id:60001) has been deleted

[msw, 2015-06-05 23:10:39]

msw@chromium.org changed reviewers:
+ sky@chromium.org

[msw, 2015-06-05 23:11:00]

Hey Scott, please take a look; thanks!

[sky, 2015-06-05 23:26:41]

LGTM

[jbudorick, 2015-06-05 23:27:49]

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

[jbudorick, 2015-06-05 23:27:50]

build/android/ lgtm

[msw, 2015-06-05 23:27:57]

The CQ bit was checked by msw@chromium.org

[commit-bot: I haz the power, 2015-06-05 23:29:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1143223005/80001

[commit-bot: I haz the power, 2015-06-06 00:31:42]

Committed patchset #3 (id:80001)

[commit-bot: I haz the power, 2015-06-06 00:32:41]

Patchset 3 (id:??) landed as
https://crrev.com/ecce673617583e7f020518791b97dca6eeccef9e
Cr-Commit-Position: refs/heads/master@{#333186}