Instead of TextPaintable fragments being an offset+length view into the
layout node, they are now a view into the paintable instead.
This removes an awkward time window where we'd have bogus state in text
fragments after layout invalidation but before relayout. It also makes
the code slightly nicer in general, since there's less mixing of layout
and painting concepts.
...to avoid allocating a copy of glyph run for painting commands. We
can't simply save pointers to a glyph run in layout/paintable tree
because it should be safe to deallocate layout and paintable trees
after painting commands are recorded, if in the future we decide to
move command execution to a separate thread.
Recently, we moved the resolution of CSS properties that do not affect
layout to occur within LayoutState::commit(). This decision was a
mistake as it breaks invalidation. With this change, we now re-resolve
all properties that do not affect layout before each repaint.
This change introduces a method for direct access to the paintable of
a PaintableFragment. This method is intended to replace the usage of
the layout node pointer. Currently, we are only eliminating the use
of `layout_node()` in hit testing.
Additionally, we no longer check if a fragment's layout node is a
`BlockContainer` before recursing into its children during hit testing.
This check was likely relevant when all fragments were owned by
`PaintableWithLines`, but now it should be safe to remove this check.
Rather than resolving the text-shadow each time painting commands are
recorded, we can resolve it once during the layout commit and save the
resolved values in paintable fragments. This is also step towards
getting rid of layout node pointer in paintable fragment.
This is a part of refactoring towards making the paintable tree
independent of the layout tree. Now, instead of transferring text
fragments from the layout tree to the paintable tree during the layout
commit phase, we allocate separate PaintableFragments that contain only
the information necessary for painting. Doing this also allows us to
get rid LineBoxes, as they are used only during layout.
