Microsoft's adoption of the Chromium engine for its revamped Edge browser has meant that the company is actively participating in the development of the Chromium project, which powers browsers like Google's Chrome, Opera and Vivaldi. The contributions Microsoft makes can then be used by all of these browsers.
One new addition to the Chromium base that the company's engineers are working on is to change the default spellchecker, Hunspell, with its homegrown Windows spellchecker. The commit reads:
his CL aims to implement windows spellchecker integration in Chromium project, so that user can switch to use windows spellchecker or hunspell spellchecker at run time. We need to implement platform agnostic interfaces to integrate windows spellchecker into Chromium. We also need to refactor some code to enable runtime switch between Windows spellchecker and hunspell spellchecker.
As such, while Microsoft isn't looking to replace the default spellcheck option, it is working on providing Windows users with the option to use the OS' native spellcheck option, if they so desire. A flag to "Use the Windows OS spellchecker" is already available in the latest Chrome Canary build, though it seemingly doesn't do much as of now. The Canary build of Edge doesn't even have the flag yet, so it seems it may be sometime before the feature is finalised.