Add multiplex worker support to dexbuilder

[Bencodes]

Adding full support for multiplexed dexbuilder workers. This PR is a continuation of #14623 (comment) where we added basic worker support.

Related issue: #10241

[nkoroste]

Any updates on this?

[ted-xie]

Oops, sorry for messing with the labels - I got some of my browser tabs mixed up. From a glance I don't see any major red flags; I'll discuss this internally.

[ted-xie]

Overall looks good - would you mind adding a test for this flag in src/test/shell/bazel/android/android_integration_test.sh?

[ted-xie]

Actually, disregard my previous comment. I'll take care of the integration test. Overall LGTM, I'll push this through the internal processes.

[ahumesky]

Rather than adding a separate flag, there's --modify_execution_info:

https://bazel.build/reference/command-line-reference#flag--modify_execution_info

So I think we could do the same thing with:

--modify_execution_info=DexBuilder=+supports-multiplex-workers

I believe that --modify_execution_info was added after --use_workers_with_dexbuilder was added, so that's why we have that hardcoded flag. We could actually remove --use_workers_with_dexbuilder as well and replace it with --modify_execution_info.

--modify_execution_info is admittedly a little clunkier than a specially purposed flag, but on the other hand, it might be better than proliferating several more flags.

[larsrc-google]

Very much agree that we shouldn't add another tool-specific flag.

I'm starting to regret the --experimental_worker_multiplex flag being a boolean instead of a include/exclude list.

[Bencodes]

What about instead of flag proliferation we introduce an expansion CLI flag that sets all of the necessary --modify_execution_info requirements for Android multiplex workers?

[Bencodes]

The CLI expansion solution would look something like this. #15950

[ahumesky]

Thanks everyone, let's go with #15950

[nkoroste]

should we close this in favor of #15950 to avoid confusion

[ahumesky]

Yes that sounds good