This adds TShadowRoot to the `dom` module.
Right now it barely adds uses of it, but this is a prerequisite to fix a bunch
of Shadow DOM bugs and separate it from the XBL mess.
The key here is that we only filter longhands if the shorthand is accessible to
content and vice-versa. This prevents the bug that prevented me to land this
patch before, which was us not expanding properly chrome-only shorthands.
Again, this is incomplete, and I need to teach LonghandsToSerialize to get a
potentially incomplete list of properties, and all that.
More improvements to come. In particular, this still iterates through Shadow DOM
in each_xbl_cascade_data, but that should be changed later. That allows to
cleanup a bunch of stuff and finally fix Shadow DOM cascade order.
We still rely on the binding parent to be setup properly in the shadow tree, but
that requirement can go away later (we can walk the containing shadow chain
instead).
This mostly focuses on removing the XBL binding from the Shadow host.
It'd be nice to do EnumerateShadowRoots faster. I think that should also be a
followup, if needed.
Bug: 1425759
Reviewed-by: xidorn
MozReview-Commit-ID: Jf2iGvLC5de
We are relying in the XBL binding for the shadow host, we need to check
explicitly.
Also, we were checking in_shadow_tree, which is really broad. Just
is_html_slot_element should do, since the rest of the nodes should have only
light tree children.
Bug: 1425759
Reviewed-by: xidorn
MozReview-Commit-ID: KAFRVxaLsK
It's just a struct aggregating stylesheets + CascadeData, with a quirks_mode
parameter because XBL sucks so bad.
Bug: 1436059
Reviewed-by: xidorn
MozReview-Commit-ID: 7q99tSNXo0K
Now that we have an Element around on cascade, we can stop using the cascade
flags mechanism to pass various element-related state, like "is this element the
root", or "should it use the item-based display fixup".
That fixes handwaviness in the handling of those flags from style reparenting,
and code duplication to handle tricky stuff like :visited.
There are a number of other changes that are worth noticing:
* skip_root_and_item_based_display_fixup is renamed to skip_item_display_fixup:
TElement::is_root() already implies being the document element, which by
definition is not native anonymous and not a pseudo-element.
Thus, you never get fixed-up if your NAC or a pseudo, which is what the code
tried to avoid, so the only fixup with a point is the item one, which is
necessary.
* The pseudo-element probing code was refactored to return early a
Option::<CascadeInputs>::None, which is nicer than what it was doing.
* The visited_links_enabled check has moved to selector-matching time. The rest
of the checks aren't based on whether the element is a link, or are properly
guarded by parent_style.visited_style().is_some() or visited_rules.is_some().
Thus you can transitively infer that no element will end up with a :visited
style, not even from style reparenting.
Anyway, the underlying reason why I want the element in StyleAdjuster is because
we're going to implement an adjustment in there depending on the tag of the
element (converting display: contents to display: none depending on the tag), so
computing that information eagerly, including a hash lookup, wouldn't be nice.
