Refactor: extract resolver_query_adapter as an injectable dependency.

[myronmarston]

This paves the way for further refactoring I'm working on.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}