GitLab

The --disk-cache-dir flag allows to use custom disk cache folder instead
of using the one inferred from user data directory.

BUG=882431
R=caseq

Change-Id: I2da7e1c4b72eda32bccf6851c66ce44c1aaa837d
Reviewed-on: https://chromium-review.googlesource.com/c/1359038Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Commit-Queue: Andrey Lushnikov <lushnikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613297}