Only consider as touchCapable if primary pointer is touch

[conjuncts]

I think an improvement is that when mathVirtualKeyboardPolicy is 'auto', the virtual keyboard should only be shown (by default) if the user's device's primary pointer is touch, not just if touchscreen is supported.

My personal use case is as follows. I have a touchscreen laptop with two modes of input, keyboard and touchscreen. In normal use, I only use the regular keyboard, and the virtual keyboard is not useful. In this case, window.matchMedia("(pointer: coarse)").matches == false. Although I am able to use the touchscreen when upright, in most cases I don't. Instead, when I wish to use the touchscreen, I physically fold the laptop. This causes an OS level change that disables the keyboard and also causes chrome to say window.matchMedia("(pointer: coarse)").matches == true. Thus, changing this one line conveniently addresses my use case.

I don't think this change would affect traditional desktops or plain touch devices; it only improves UX for devices with both touch and keyboard. This described behavior is consistent to the behavior of most other apps on my laptop: only when I enter "fold mode" does the OS virtual keyboard appear.

[arnog]

Yes, that's a good point. I should probably rename isTouchCapable to isTouchModeEnabled to be more descriptive.