What is the expected behavior of scrollable divs within touch screen devices, and does ARIA apply?

This is a question I've been asked several times lately, and I'm not sure
there is a suitable answer.

 

Basically, if you have a scrollable div, such as the following:

 

<div tabindex="0" class="scrollable">

Internal markup and content.

</div>

 

Where the class 'scrollable' includes the rules for setting a specific
height/width and overflow:auto.

 

This occurs all over the web to reduce screen real estate, and is happening
quite a bit on mobile devices where this is premium.

 

So, for iOS touch screen devices using VoiceOver, you can move focus into
the content region, then swipe up and down with one finger to scroll through
the content.

E.G

http://whatsock.com/tsg/Coding%20Arena/Scrollable%20Divs/Scrollable%20Div%20
(Internal%20Content)/demo.htm

 

However, there is no native way to identify when a particular region is
scrollable. Adding role="region" and aria-label="Scrollable" does nothing at
all and is not conveyed. To my knowledge, this works even less intuitively
on the Android using TalkBack. This makes it impossible for a blind user to
know that content is scrolled offscreen within a particular region of the
UI.

 

The only ARIA equivalent that seems like it may have some value is
role=scrollbar

http://www.w3.org/TR/wai-aria/roles#scrollbar

Though this refers to a trackbar or graphic, and doesn't actually apply in
this case.

 

So I guess my question is, is there a documented method for implementing a
label to convey that a region is scrollable for touch screen devices?

If there is not, should there be one?

And if there is, do touch screen devices support it?

 

I'm not sure where the breakdown is.

 

Side note: If you hear scrollable in the above demo, it's because I cheated
by using an offscreen positioned live region to announce "scrollable" when
focus is first set into the region with VoiceOver running. No other method
worked for doing this.

 

Thanks,

Bryan