This is part of a larger refactoring:
1) Add new method and provide default implementations for the other
Create* methods (this CL) so they can be removed downstream.
2) Implement new method in Chromium and remove the overrides of the
other Create* methods from subclasses of PacketSocketFactory.
3) Remove other Create* methods from PacketSocketFactory and make
the new Create method pure virtual. Make BasicPacketSocketFactory
take user_agent and proxy_info in the constructor.
4) Move the slimmed-down packet_socket_factory into api/.
Bug: webrtc:7447
Change-Id: I961fcc4451c9fb2bc7a049b8f57d5894209fd262
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/150941
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Patrik Höglund <phoglund@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29026}
a42b63267c