API for scrolling

I think several users (ilpianista in IRC, emdek, me) would appreciate an API for scrolling, similar to QWebFrame::scroll/scrollPosition/scrollToAnchor/scrollBar*.

There also should be a signal when the scroll position was changed.

Use cases which come to mind:

• Displaying the scroll percentage in a statusbar
• Updating that scroll percentage without polling
• Storing/retrieving scroll position
• Scrolling to a given anchor on load
• Scrolling the page programatically, e.g. for automation, etc.