Bug 1860834 [wpt PR 42717] - Give <slot> element default unicode-bidi…

…: isolate style., a=testonly

Automatic update from web-platform-tests
Give <slot> element default unicode-bidi: isolate style.

This is behind the RuntimeEnabledFeatures::CSSPseudoDirEnabled() flag.

This implements a part of the behavior described in:
whatwg/html#3699 (comment)
which has been specified in:
whatwg/html#9554
whatwg/html#9796

Bug: 576815
Change-Id: Ice471838c7251fc69d87abfa723f3eef1a4c455a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4800075
Reviewed-by: Chris Harrelson <chrishtrchromium.org>
Reviewed-by: Di Zhang <dizhanggchromium.org>
Commit-Queue: David Baron <dbaronchromium.org>
Cr-Commit-Position: refs/heads/main{#1214439}

--

wpt-commits: a79306e06659bde55be85c3af5c1d7d4a51c0cbd
wpt-pr: 42717

UltraBlame original commit: c1d0594b7c2341b1247e69987405d8038e57308b

testing/web-platform/tests/html/rendering/bidi-rendering/slot-isolate-001-ref.html

@@ -0,0 +1,118 @@
+<
+!
+DOCTYPE
+html
+>
+<
+title
+>
+HTML
+Rendering
+:
+slot
+element
+has
+unicode
+-
+bidi
+:
+isolate
+<
+/
+title
+>
+<
+link
+rel
+=
+"
+author
+"
+title
+=
+"
+L
+.
+David
+Baron
+"
+href
+=
+"
+https
+:
+/
+/
+dbaron
+.
+org
+/
+"
+>
+<
+link
+rel
+=
+"
+author
+"
+title
+=
+"
+Google
+"
+href
+=
+"
+http
+:
+/
+/
+www
+.
+google
+.
+com
+/
+"
+>
+<
+div
+style
+=
+"
+unicode
+-
+bidi
+:
+bidi
+-
+override
+;
+direction
+:
+ltr
+;
+"
+>
+&
+#
+x5D0
+;
+-
+&
+#
+x5D1
+;
+<
+/
+div
+>
+<
+div
+>
+isolate
+<
+/
+div
+>