`parsed_root.path` already contains the leading slash in the the URL, so adding
an additional slash gives an incorrect URL.

Change-Id: I84f04179356bb132a31531232a5c30c7808f7c1b
Reviewed-on: https://chromium-review.googlesource.com/520724Reviewed-by: Paweł Hajdan Jr. <phajdan.jr@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: David Tu <dtu@chromium.org>