Apply HSTS to WebSocket connections.

With this change, ws: connections to hosts which have an existing HSTS
pin will be automatically changed to use wss:, ie. SSL.

In addition, Strict-Transport-Security headers that are sent from a wss:
server with a valid SSL certificate will be enforced on subsequent ws:
and http: connections to the same host.

This CL also modifies HttpNetworkTransaction to treat wss: the same as

BUG=455215, 446480

Review URL:

Cr-Original-Commit-Position: refs/heads/master@{#317252}
Cr-Mirrored-Commit: cb76ac67dca0a133cdfa96678ac5cd2a65af96a3
8 files changed