This flattened singleton module explicitly lists by module name whether source or
prebuilt version of a module should be used. If a module appears in this
metadata module, it supersedes all other source vs prebuilts selection
mechanism
Implementation details
- Update the module dep chain from <source> --> <prebuilt> to <source>
--> <prebuilt> --> all_apex_contributions
- all_apex_contributions sets a provider which is bubbled up
to the source module. This requires changing `prebuilt_select` to a
bottom up mutator
- Update `usePrebuilt` to consult the new provider before falling back
to existing source vs selection mechanisms. If (foo|prebuilt_foo) is
listed in the selected `apex_contributions` modules, it
will be used superseding any other selection mechanisms.
- Update this depTag to IsMetaDepTag so that bootclasspath_fragment's
validation ignores this new dependency.
Test: Added unit tests to assert that this new mechanism supersedes
`use_source_config_var`
Bug: 308174768
Change-Id: I39a85639642711f3c96b6f18b94d626b55e80c66
1c4d94dccf