Instead of string splitting every time you call Element::has_class(),
we now split the "class" attribute value when it changes, and cache
the individual classes as FlyStrings in Element::m_classes.
This makes has_class() significantly faster and moves the pain point
of selector matching somewhere else.
This display type is implemented using a LayoutBlock that is_inline().
Basically it behaves like a block internally, and its children are laid
out in the normal block layout fashion. Externally however, it behaves
like an atomic inline-level box.
Layout of inline-block boxes happens in three stages:
1. The outer dimensions of the block are computed during the recursive
normal layout pass. We skip positioning, but lay out children.
2. Later on, during line layout in the *containing block*, the inline
block now contributes a linebox fragment. When linebox fragments are
positioned, we learn the final position of the inline block. That's
when we set the inline block's position.
3. We re-layout the inline block's children once again. This is done to
make sure they end up in the right position. The layout tree doesn't
use relative offsets, so after we position the inline block in (2),
its children will not have its positions updated. Relayout moves
all children of inline blocks to the right place.
This is a rather naive approach but it does get the basic behavior into
place so we can iterate on it. :^)
Getting the innerHTML property will recurse through the subtree inside
the element and serialize it into a string as it goes.
Setting it will parse the set value as an HTML fragment. It will then
remove all current children of the element and replace them with all
the children inside the parsed fragment.
Setting element.innerHTML will currently force a complete rebuild of
the document's layout tree.
This is pretty neat! :^)
