In a case where document already has text selection and Selection.addRange() is called, Blink merges the Range and the existing text selection into one if they have overlap, and does nothing otherwise. We'll change it so that Blink always ignore the Range. It matches to Edge.
Docs: https://github.com/w3c/selection-api/issues/80 https://developer.mozilla.org/en-US/docs/Web/API/Selection/addRange