Any property that allows a numeric type (either a <number>, <integer>, or a number with a unit like a <length> or <percentage> or any other dimension type) can also be a math function such as calc(). These require special handling in the code to store the calculation, and resolve them when needed.

Generally:

• If the property has bespoke parsing code, that code needs to make sure that any parsing functions it uses also handle math functions. (The methods that parse a numeric type as a CSSStyleValue all do this already.)
• The property's value in StyleProperties.h needs to be a type that can store a math function - for example, for Length that would be LengthOrCalculated. Note that the *Percentage types can also store math functions.
• The StyleProperties getter for the property, if it has one, needs to also check for math values and resolve them. That will likely require passing in a Layout::Node.

The following properties have been identified by the Tests/LibWeb/Text/input/css/calc-coverage.html test added in #1788. Others might pass this test but not handle math functions later on in the process - I'll try and add those when I spot them.

• filter functions in filter and backdrop-filter
• grid-auto-columns
• grid-auto-rows
• grid-template-columns
• grid-template-rows
• transform-origin

Please rebaseline Tests/LibWeb/Text/input/css/calc-coverage.html when fixing any of these!