Refactor of P2PTransportImpl for crypto config.

This change refactors the P2PTransportImpl to take in a factory that can
create a QUIC client or server crypto configuration. This allows a
cleaner interface for injecting the crypto configurations, and removes
the hacky interface that was used for testing to inject a failing crypto
configuration.

Bug: 874296
Change-Id: I3268b258b38fe8ff1d57717bd8185b4a9701dd09
Reviewed-on: https://chromium-review.googlesource.com/c/1407924
Commit-Queue: Seth Hampson <shampson@chromium.org>
Reviewed-by: Steve Anton <steveanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623717}
9 files changed