The original name was based on the window.getComputedStyle() API.
However, "Computed" in "getComputedStyle" is actually a misnomer that
the platform is stuck with due to backwards compatibility.
What getComputedStyle() returns is actually a mix of computed and used
values. The spec calls it the "resolved" values. So let's call this
declaration subclass "ResolvedCSSStyleDeclaration" to match.
Rather than destroying and rebuilding the entire document layout tree in
every call to `ComputedCSSStyleDeclaration::property()`, we now just
make sure that the layout tree exists.
This speeds up the DOM Inspector significantly, from taking several
seconds to select an element, to almost instant. :^)
getComputedStyle(element) now returns a ComputedCSSStyleDeclaration
object, which is a live view of the computed style of a given element.
This works by ComputedCSSStyleDeclaration being a wrapper around an
element pointer. When you ask it for a CSS property, it gets the latest
computed style values from the element and returns them as a
CSS::StyleProperty object.
This first cut adds support for computed 'color' and 'display'.
In case the element doesn't have a corresponding node in the layout
tree, we fall back to using specified style instead. This is achieved by
performing an on-the-fly style resolution for the individual element and
then grabbing the requested property from that resolved style.
