Translates iframe-relative coordinates to document-relative coordinates using
getBoundingClientRect of the WebView iframe. The platform never scales the iframe element itself
(content zoom scales marked areas inside it), so an inner pixel is an outer pixel.
Translates iframe-relative coordinates to document-relative coordinates using getBoundingClientRect of the WebView iframe. The platform never scales the iframe element itself (content zoom scales marked areas inside it), so an inner pixel is an outer pixel.