Using a custom UIPresentationController with horizontally compact UITraitCollection, but a popover otherwise
<p>I have a view controller that I'm presenting in a universal iOS application. On the iPhone, it displays using a custom UIPresentationController which adjusts the frame of the presented view using <code>UIPresentationController</code>'s <code>frameOfPresentedViewInContainerView</code> method. This is working fine, however...</p>

<p>On iPad, I'd like the same view controller to display as a popover when the <code>UITraitCollection</code> has a <code>Regular</code> width, but to switch to my custom UIPresentationController when in <code>Compact</code> width. Is this achievable?</p>