Merge 122432 - [Shadow DOM] <video> with <shadow> crashes
Reviewed by Kent Tamura.
This is similar to Bug 90480, where an undesired renderer is created by
locating an insertion point on the shadow boundary.
This change adds a guard for such case by cheking whether the
source node of each to-be-created renderer comes from the UA shadow
tree, which is allowed to have a renderer.
(WebCore::HTMLMediaElement::childShouldCreateRenderer): Added a check.
(WebCore::HTMLMediaElement::mediaControls): Added const.
(WebCore::HTMLMediaElement::hasMediaControls): Added const.
* fast/dom/shadow/insertion-point-video-crash-expected.txt: Added.
* fast/dom/shadow/insertion-point-video-crash.html: Added.