Recently deprecated RangeError.checkValidIndex in this CL needs to be fixed in lib/web_ui/lib/src/engine/services/buffers.dart for flutter/engine.

There's a tryjob breakage due to this deprecation.
https://ci.chromium.org/ui/p/dart/builders/ci.sandbox/flutter-analyze/17865/overview

Change all instances of RangeError.checkValidIndex in favor of IndexError.check.