[Cronet] Add QUIC experimental params

[Cronet] Add QUIC experimental params

This CL plumbs four QUIC experimental params (
quic_store_server_configs_in_properties,
quic_delay_tcp_race,
quic_max_number_of_lossy_connections,
quic_packet_loss_threshold) from Cronet's
setExperimentalOptions API to net::HttpNetworkSession.

This CL also adds a unittests target to run the unittests.
A followup CL will enable the unittests on the cronet bots.

BUG=545118
NOTRY=true
NOPRESUBMIT=true

Committed: https://crrev.com/fde0b72c603cd111c36ca4cc416d82a7395bcf6c
Cr-Commit-Position: refs/heads/master@{#360454}

Committed: https://crrev.com/8ece3aa6845350c1971a3e824bf148f3e8de3253
Cr-Commit-Position: refs/heads/master@{#360875}

Review URL: https://codereview.chromium.org/1448583003

Cr-Commit-Position: refs/heads/master@{#361138}
(cherry picked from commit f24ee5f5afeb59d2a9134a7b986efb6483629fe5)

[xunjieli, 2015-11-30 18:26:34]

xunjieli@chromium.org changed reviewers:
+ mef@chromium.org

[xunjieli, 2015-11-30 18:26:34]

PTAL

[mef, 2015-11-30 19:01:59]

lgtm

[xunjieli, 2015-11-30 19:03:30]

The CQ bit was checked by xunjieli@chromium.org

[commit-bot: I haz the power, 2015-11-30 19:08:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1483103002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1483103002/1

[commit-bot: I haz the power, 2015-11-30 19:14:17]

Committed patchset #1 (id:1)