Extact Chooser intent processing; remove delegate

This CL makes two small cleanups with no observable behavior changes:

 1. Extract a helper (in a new component) to handle the intent
    processing that was previously inline in ChooserActivity's
    onCreate(), storing the validated request data immutably. There's
    a lot of boilerplate in the processing that was too verbose
    inline in such an important lifecycle hook, and this refactoring
    clarifies the lifecycle -- many of the extracted parameters had
    been individual ivars on ChooserActivity, and it wasn't obvious
    that they were all assigned in a batch and then never modified.

 2. In previous code reviews, ayepin@ and I have discussed the
    opportunity to remove the ChooserListCommunicator interface now
    that it's clearly only responsible for providing values that we
    can precompute and inject upfront; that precomputation mostly
    involves the parameters extracted in this CL, so I've gone ahead
    and made that change here. (It's not as straightforward to
    replace the base ResolverListCommunicator, so for now we're still
    passing through the same "communicator object" as before, but
    without the enhanced "chooser-specific" API.

Test: atest IntentResolverUnitTests
Bug: 202167050
Change-Id: I7c3d47d282591f86ab1fae5e04c3d7d83f2fea0d
5 files changed