This is needed to better support emitting mouse button events when
pressing tablet buttons. It's common in many art programs that an action
is tied to a mouse button + a modifier, such as panning the canvas. So
being able to send keyboard modifiers in tandem with mouse buttons is
very useful when rebinding.
Tests are added for this new feature.
CCBUG: 469232
Since the tablet cursor and the mouse cursor is tracked separately,
rebinding a tablet button to a mouse click is sort of wonky. For
example, if you assign it to Right Click and attempt to open a context
menu it will appear to open in the wrong place.
So before we send the mouse button event, set the mouse position to
the tablet cursor position. A test is added to ensure this functionality
works as intended and doesn't regress.
This is to not destroy the tablet state for the next test (which is
added in the next commit.) We could also explicitly do a tablet tool
up/down dance here, but all we need is the tablet tool to be in
proximity for the tablet button event to fire.
This adds autotests for binding to tablet pad and tool buttons, which
was previously untested. Of note is that we don't explicitly test mouse
buttons, which is already tested in the other functions.
