Use struct AlternativeService in OnAltSvc() and OnSpdyAltSvc() methods.

Use struct AlternativeService parameter in
SpdyFramerVisitorInterface::OnAltSvc() and SpdyDispatcher::OnSpdyAltSvc()
methods.  This is in preparation for handling multiple alternative services that
a single HTTP/1.1 header field or HTTP/2 frame can carry.

This CL lands server change 94293057 by bnc.

BUG=392575

Review URL: https://codereview.chromium.org/1171183002

Cr-Commit-Position: refs/heads/master@{#333717}
10 files changed