+ayatane thoughts on this approach? https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/1141354

also this https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/1141357

Re #1, I don't see any immediate issues with this approach, just that symlinks tend to cause a set of issues around canonical paths and same-but-different file detection.

I was worried based on a discussion with pprabhu that I would have to worry about common.py files in repos other than autotest, but I think I have ruled that out.

akeshet@akeshet:~/chromiumos/src$ find -name common.py | grep -v autotest | xargs cat | grep autotest
-> no results

Actually ^ was a bad approach, and I do see some common.py files elsewhere.

./platform/ap-daemons/autotest/client/common_lib/cros/jetstream/common.py
./platform/ap-daemons/autotest/client/cros/jetstream/common.py
./platform/ap-daemons/autotest/server/cros/jetstream/external/common.py
./platform/ap-daemons/autotest/server/cros/jetstream/tools/common.py

I don't like the idea of inter-repository symlinks, so for ^ I will take the approach of just duplicating client_common.py and nonclient_common.py once https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/1142454 is landed

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/051932709036ab7b94d49aaeecc23fdb57008253

commit 051932709036ab7b94d49aaeecc23fdb57008253
Author: Prathmesh Prabhu <pprabhu@chromium.org>
Date: Fri Jul 20 18:41:09 2018

Excise wardmodem.

This never got added to a suite, is ~5 years old at this point and
causing maintenance overhead. I am quite sure at this point it'd be
better to write something like this in a statically typed language
(think go).

Burn my old sins.

BUG=chromium:864860
TEST=None

Change-Id: I9201f424e1168097e0671dae9a2ab733d7ff1c40
Reviewed-on: https://chromium-review.googlesource.com/1144199
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Prathmesh Prabhu <pprabhu@chromium.org>
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>

[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/site_tests/cellular_Smoke/control.wardmodem_e362
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/state_machines/request_response_unittest.py
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[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/state_machines/network_identity_machine.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/state_machines/__init__.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/global_state.py
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[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/at_transceiver_unittest.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/at_channel.py
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[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/wardmodem_exceptions.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/state_machines/common.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/configurations/base.conf
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/state_machines/network_registration_machine.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/task_loop_unittest.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/__init__.py
[modify] https://crrev.com/051932709036ab7b94d49aaeecc23fdb57008253/client/cros/cellular/test_environment.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/global_state_unittest.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/state_machines/network_identity_machine_unittest.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/state_machine_unittest.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/common.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/wardmodem.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/at_channel_unittest.py
[delete] https://crrev.com/143fe69d61fa223577b06596cd01ee39ab3f1062/client/cros/cellular/wardmodem/configurations/e362.conf