Fix caret position updating with touch events in chrome

[Ge-lx]

There has been an issue in Chromium for quite a while (> 5 years) now, which breaks changing the caret position via touch events.

I have provided more details about the bug in #5844.

While the fix is not the most elegant - I have to admit - it should not break anything else since it only interferes with Chrome environments where there is an .activeTouch. It did not break any tests for me.

[marijnh]

I'm a bit skeptical about this not breaking anything—it looks like it will freeze the display as long as a touch event is active, which could, if you make, for example, a programmatic change while a touch is active, leave the editor displaying the wrong state.

Have you looked into kludges that focus on clearing activeTouch more proactively? For example, store the touch target in that object, and when it isn't part of the editor anymore after a display update, clear activeTouch?

[Ge-lx]

How would that fix the issue of the missing caret position update?

I also just noticed that I referenced the wrong chromium bug. I think this one is more appropriate and explains the underlying issue a bit better.

Sorry, I don't have the resources to dig into the code that much, so I cannot offer any help on more sophisticated mitigation methods. My hope is that the browser bug gets addressed and we receive at least a touchcancel event to which we can react.