C++11 in-class member initialization in Call configs.

BUG=
R=mflodman@webrtc.org, pbos@webrtc.org

Review URL: https://codereview.webrtc.org/1166263004.

Cr-Original-Commit-Position: refs/heads/master@{#9416}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 78fb3b3f8f8f46e3b5b62c94177713dc05f53947
3 files changed