GitLab

Element::CanAttachShadowRoot() needs to be updated because it returns wrongly true for
customized built-in elements.

The spec: https://dom.spec.whatwg.org/#dom-element-attachshadow

Bug: 823033
Change-Id: Ia9aeb47569414830f5435f37f85d96101b9fe432
Reviewed-on: https://chromium-review.googlesource.com/970142Reviewed-by: Koji Ishii <kojii@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Hayato Ito <hayato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545026}