Interface for communicating with the built-in drag and drop
 implementation in the content area. Use this to register where
 the listeners should attach (something that implements
 |nsPIDOMEventTarget| which is what we end up using under the hood).
[scriptable, uuid(4f418f58-f834-4736-a755-e0395bedca9d)]
interface nsIDragDropHandler : nsISupports


 Unregister all handlers related to drag&drop
void detach()
 Attach drag handlers to receiver specified by |attachPoint| and
 specify callbacks to allow overriding of the built-in behaviors.

 @param attachPoint hookup listeners to this location
 @param navigator loads dropped urls via this interface. If NULL, 
                   the client must handle the drop itself, either
                   through the method provided via |overrideDrop| or
                   by letting the event bubble up through the DOM.
void hookupTo(in nsIDOMEventTarget attachPoint, in nsIWebNavigation navigator)