hterm: pause cursor blinking while the user is typing
hterm: pause cursor blinking while the user is typing

Whenever we see a keystroke from the user, we should pause the cursor
blinking momentarily.  This is a common behavior in other terminals,
and it helps when typing a lot, or moving the cursor around with the
arrow keys.

Bug: chromium:773092
Change-Id: I2a963ed9195cd7325c27024b6add688ca1ea6ace
Reviewed-on: https://chromium-review.googlesource.com/c/apps/libapps/+/1870832
Reviewed-by: Joel Hockey <9ecfc52dc2ffef73afac73f3495f294aeddf1231@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

chromium/hterm,chromium/hterm,chromium/hterm,chromium/hterm