GitLab

Old test was loading http://mock/bad and because this URL did not
exist the load was failing because of DNS resolution error.

New test uses EmbeddedTestServer, which closes the socket to simulate
ERR_INTERNET_DISCONNECTED error.

Bug: 694662
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Iaca523e8153a2c4cca0e1f174652ed48f22cabd3
Reviewed-on: https://chromium-review.googlesource.com/1035610
Commit-Queue: Eugene But <eugenebut@chromium.org>
Reviewed-by: Danyao Wang <danyao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555316}