GitLab

This CL adds special_case_urls.md to explain some of the interesting
or unexpected corner cases that can occur for certain types of URLs,
which may affect how other features are designed and implemented.

BUG=1015882

Change-Id: I311d1c4c5b4962dba8b842c20200c344eacb46d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2225374
Commit-Queue: Charlie Reis <creis@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Fergal Daly <fergal@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782856}