For clarity, I introduce <LayoutDom<Element>>::parent_node_ref to contain
the remaining unsafety bits out of composed_parent_node_ref which is more
complex than just a field access.
They don't do anything fancy so there is no additional unsafety calling them
compared to using LayoutDom in the first place, the usual story of all
those changes.
This safe method is the basic block to access element attributes from layout.
We reuse it in the other attr-related layout methods to remove a pretty big
source of rampant unsafe code between script and layout.
Layout viewer for layout 2020
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
This PR makes layout 2020 dump the box and fragment tree states into json files that can be visualized with the layout viewer tool. This tool has not much functionality other than displaying these trees and allowing to inspect each node additional data, so there is a lot of room for improvements. Some ideas for follow-ups:
- Make the tool create and display diffs between tree states.
- Actually allow creating new debug scopes during box tree and fragment tree construction. Right now there is a single scope created after constructing both trees, which is not ideal as it only allows looking at the reflow result.
- Right now an independent JSON file is created per reflow. It would be nice to unify the data obtained on each reflow on a single JSON, so diffs between reflows can be displayed as well.
- Dump and display the DOM tree. Link boxes to DOM nodes.
- #23339
This query is used to get the clientTop, clientWidth, clientHeight,
clientLeft properties of DOM objects. "NodeGeometry" doesn't really
capture what these properties do as they often are returning the width
of element border.
This isn't correct yet, but it is necessary to give a value in order for
scrolling from script to work. Later this should give an accurate
content box response as well as work for non-root elements.
