WS: Stop adding Keep-Alive to Connection header

When the WebSocketHandshakeReuseConnection feature was enabled,
"Keep-Alive" would be included in the Connection header. This behaviour
was copied from Firefox, however it is non-standard.

Microsoft Edge does not include "Keep-Alive" in the Connection header,
and Windows authentication works with WebSockets in Microsoft Edge. So
it is unlikely any server depeneds on the presence of "Keep-Alive".

Stop including "Keep-Alive" in the Connection header when
WebSocketHandshakeReuseConnection is enabled.

BUG=423609

Change-Id: Icaf232872c25b13951c7b22ac8d7f375eeadc9ff
Reviewed-on: https://chromium-review.googlesource.com/1131354
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574882}
2 files changed