De-@mut pipeline
Shut down the profiler in headless compositing mode
Prevent '&nbsp' from stripping as whitespace
Fix: whitespace is considered as spaces(U+0020), tabs(U+0009), and line breaks(U+000D U+000A)
De-@mut the FrameTree.
Update rust-layers submodule
Remove commented-out parts of Document.webidl and HTMLDocument.webidl.
Create a Line DisplayItem
add Element::new
trailing ws
reuse get_attribute_parts
no lowercasing for html element names
adding comment with spec URL
simplify match in CreateElementNS
simplify match in CreateElementNS
simplify namespace error cases
simplify namespace error cases
remove the ': Namesapce'
better test