The target of Squad was to calculate ComputedStyle for all nodes before (re-)attaching the layout tree. Currently we stop recalculating style in re-attach subtrees encountering nodes returning true for HasCustomStyleCallbacks(). The reason is that a couple of CustomStyleForLayoutObject() methods rely on ancestor elements being attached, so we delay StyleForLayoutObject until the AttachLayoutTree call.
Identified methods which needs to be fixed:
SVGElement::CustomStyleForLayoutObject()
TextControlInnerEditorElement::CustomStyleForLayoutObject()
The former looks straightforward, the latter seems to be a bit of work.
Comment 1 by bugdroid1@chromium.org
, Feb 16 2018