Normalize url before checking for whitelist.

This cl normalizes a url before checking
if it has been whitelisted. This is required
because a smart user can circumvent the blocking
page by using a whitelisted url in the query part
of a url that the user wants to visit.

Bug: 1082817
Change-Id: Iba1a09c6870582bfc4af77a3f5975c41c546705f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2199994
Reviewed-by: Aga Wronska <agawronska@chromium.org>
Commit-Queue: Yilkal Abe <yilkal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#769011}