Resolve URL/target reference at a single point in SVGUseElement
The <base> URL can change between the attribute (href) is updated and
the shadow tree constructed. This causes confusion in the target
resolving code since it can produce different results at different
points in time.
Only resolve the URL on changes (to 'href'), extract the fragment
identifier and store whether the reference is local or not.
Refactor the SVGUseElement target element lookup with an eye to
future handling of "fragment-only" (local) URLs.
This makes the externalDocument in
SVGURIReference::targetElementFromIRIString unused, so remove that
codepath and simplify the function accordingly.
This changes behavior from resolving the URL and target element when
needed (depending on when layouts happen), to only when the 'href' is
mutated. This new behavior matches Edge, but not Gecko.
BUG=601203, 470608
Review-Url: https://codereview.chromium.org/2173453002
Cr-Commit-Position: refs/heads/master@{#407128}
8 files changed
