Have WebSocket work with Network Service

This CL integrates WebSocket with the network service if it's enabled.
Before this CL, blink used WebSocket in content/browser even when
the network service is enabled. As a result, cookies were not shared
between the usual requests and WebSockets. This CL fixes the test
failures.

On the other hand, the WebSocket implementation living in
/services/network still lacks some functionalities, which results in
new test failures.

 - http/tests/security/cookies/websocket/third-party-cookie...
   I guess these failures share the same cause with
   http/tests/security/cookies/third-party... failures, and will be
   fixed altogether.
 - http/tests/websocket/multiple-connections-throttled.html
   This will be fixed the the throttling is implemented.
 - http/tests/devtools/websocket/websocket-handshake.js
   I don't know why this test fails. I will investigate.
 - Browser tests
   This is caused by the lack of WebRequest API support. I will work
   on it.

Bug: 721400
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I8553be467e88f34929f5585376bdadd31b043e17
Reviewed-on: https://chromium-review.googlesource.com/964105
Commit-Queue: Yutaka Hirano <[email protected]>
Reviewed-by: Kinuko Yasuda <[email protected]>
Reviewed-by: Yuri Wiitala <[email protected]>
Reviewed-by: Adam Rice <[email protected]>
Cr-Commit-Position: refs/heads/master@{#545390}
15 files changed