This is a lot nicer than first_child_with_tag_name(...).
The is<T>(Node) functions are obviously unoptimized at the moment,
and this is about establishing pleasant patterns right now. :^)
These helpers return the next/previous sibling Node that's actually an
element. This will be useful in the CSS engine since CSS doesn't care
about text nodes.
Instead of branching on the Node type, let subclasses decide how their
layout nodes get constructed.
This will allow elements to create custom layout nodes if they want.
This patch implements basic support for presentational hints, which are
old-school HTML attributes that affect style.
You add support for a presentational hint attribute by overriding
Element::apply_presentational_hints(StyleProperties&) and setting all
of the corresponding CSS properties as appropriate.
To make the background color fill the entire document, not just the
bounds of the <body> element's LayoutNode, we special-case it in the
HtmlView::paint_event() code for now. I'm not entirely sure what the
nicest solution would be, but I'm sure we'll discover it eventually.
You can now query Document::title() to get a String containing whatever
is inside the document's <title> tag.
In support of this, this patch adds the <html>, <head> and <title>
elements.
We now show a tooltip for the hovered node's enclosing HTML element's
title attribute, if one is present.
This patch also adds HTMLHeadingElement. The tags h1-h6 will now create
the right kind of objects.
This also fixes another bug with inline wrappers. Namely,
we should only add inline wrappers if a block node has
both non-block (inline or text) and block children.
