GitLab

Move the implementation of GURL::DomainIs into a shared function in url_util/,
to be used both by GURL and url::Origin.

The reason for this refactoring is to reap significant performance gains in
scenarios where previously url::Origins had to be converted to GURLs for
DomainIs checks. This involved string copying, allocations, and parsing the
entire URL once again.

BUG=517560

Review-Url: https://codereview.chromium.org/2287483002
Cr-Commit-Position: refs/heads/master@{#415606}