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This will permit Windows authentication to work with WebSockets. See
Intent to Ship thread:
https://groups.google.com/a/chromium.org/d/msg/blink-dev/kEtUcy7W0fU/dTyvzUy0BgAJ

Turn on the WebSocketHandshakeReuseConnection feature by default.

Test coverage for the old behaviour has been removed; since the flag
itself will be removed in the next version, this seems acceptable.

BUG=423609

Change-Id: I1373b7b4adcfe695f56a174a7fed2a3bd67ad56b
Reviewed-on: https://chromium-review.googlesource.com/c/1283349Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600045}