In flutter/engine#53083 the test for a "simple" round rect was relaxed in one case by using fuzzy comparisons of the radii values, but made more restrictive in another case by requiring the X and Y radii to match.

The Skia definition of a "simple" round rect - and the definition that matches the code inside the if block - is that the X and Y radii can be different, but they must be the same X,Y at each corner.