Use Element::LocalNameForSelectorMatching in InvalidationSet

To match ElementRuleCollector et al. We will lower-case tag names on
(selector) parsing in HTML documents, and thus need to give the same
treatment to the local name extracted from the element.

Bug: 856368
Change-Id: I07e726864de048f5948cb27fa7e5dd6eaad9b0ef
Reviewed-on: https://chromium-review.googlesource.com/1202206
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588427}
2 files changed