Add roundtrip tests to SpdyAltSvcWireFormat.

Add roundtrip tests to SpdyAltSvcWireFormat.

SpdyAltSvcWireFormat performs two distinct roles: parsing and serializing.  This
CL adds roundtrip tests to make sure that these functionalities are compatible.

This CL lands server change 105756554 by bnc.

BUG=488484
Committed: https://crrev.com/b0d839cc937b4e16a8d3c820f28c52fee158fb22
Cr-Commit-Position: refs/heads/master@{#355114}

[Bence, 2015-10-20 17:41:03]

Ryan: PTAL.  Thank you.

[Bence, 2015-10-20 17:41:08]

bnc@chromium.org changed reviewers:
+ rch@chromium.org

[Bence, 2015-10-20 17:41:09]

Ryan: PTAL.  Thank you.

[Ryan Hamilton, 2015-10-20 17:57:10]

lgtm

[Bence, 2015-10-20 18:24:06]

The CQ bit was checked by bnc@chromium.org

[commit-bot: I haz the power, 2015-10-20 18:24:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1416893002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1416893002/1

[commit-bot: I haz the power, 2015-10-20 18:37:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-20 18:38:22]

Patchset 1 (id:??) landed as
https://crrev.com/b0d839cc937b4e16a8d3c820f28c52fee158fb22
Cr-Commit-Position: refs/heads/master@{#355114}