Simplify "is external URL" in filter operations resolving

We've already resolved the URL, so we might as well just use
equalIgnoringFragmentIdentifier on that rather than potentially
re-resolve and compare. No functional change.
Eventually we'll need to have the URL resolved before style resolution.

BUG=470608, 405315

Review-Url: https://codereview.chromium.org/2167733002
Cr-Commit-Position: refs/heads/master@{#406574}
1 file changed