Add test for PrefetchURLLoader::FollowRedirect() fix

This must be submitted after the fix (crrev.com/c/1415754).

Bug: 922362
Change-Id: Ib425cad15e525f4d3ecf443f6e017b4f742cb76c
Reviewed-on: https://chromium-review.googlesource.com/c/1415235
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Jun Cai <juncai@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624699}
1 file changed