This is an issue I am having with Skritter web. After updating to Chrome 70, I found that drawing characters with the stylus on my Surface Book no longer worked. Neither did touch. These had been working in past versions of Chrome, and work in Firefox.
I believe it the problem is related to this Chrome change which was released in version 70:
I went in to chrome://flags and set “Touch Events API” to “Enabled” (the default is now “Disabled”), which allows me to use Skritter with pen/touch again, so it seems likely that this change is the culprit. There are some suggested changes in the chrome page on how to detect touch screens.