Refactor P2PQuicTransportConfig to only contain values

This allows P2PQuicTransportConfig to be constructed on the main
thread and passed to the WebRTC worker thread where the
P2PQuicTransport is constructed.

This reduces the amount of boilerplate code needed to construct the
object in a cross-threaded manner as more parameters are added to
the config.

Bug: 874296
Change-Id: I3ae2f09b1c53e7b12f804c2c526d3dad29b323ff
Reviewed-on: https://chromium-review.googlesource.com/c/1330845
Commit-Queue: Steve Anton <steveanton@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607335}
14 files changed