The feature changes the behavior of FileReader API so that the result attribute is only set right before the Load event is fired. Motivation: This brings the chromium FileReader implementation in line with the FileAPI spec. The existing implementation was identified to possibly cause memory leaks but that scenario was very rarely seen, as evidenced by this experiment.
Docs: https://github.com/w3c/FileAPI/issues/79 https://crbug.com/768972 https://chromium-review.googlesource.com/c/chromium/src/+/2352610
Explainers: https://github.com/w3c/FileAPI/issues/79