Sanitize https:// URLs before sending them to PAC scripts.

This additionally strips the path and query components for https:// URL (embedded identity and reference fragment were already being stripped).

For debugging purposes this behavior can be disabled with the command line flag --unsafe-pac-url.

BUG=593759
R=mmenke@chromium.org

Review URL: https://codereview.chromium.org/1996773002 .

Cr-Commit-Position: refs/heads/master@{#395266}
(cherry picked from commit 81357b39c643fc746517fd6ce5cb2076b7ddc3f4)

Review URL: https://codereview.chromium.org/2058683002 .

Cr-Commit-Position: refs/branch-heads/2743@{#308}
Cr-Branched-From: 2b3ae3b8090361f8af5a611712fc1a5ab2de53cb-refs/heads/master@{#394939}
6 files changed