When a mousewheel scroll event isn't handled by the web content
itself (e.g. an overflowed box or similar), the event needs to get
passed back up to the OutOfProcessWebView.
The OOPWV will now detect WebContent process crashes/disconnections and
simply create a new WebContent process in its place. We also generate a
little error page with a link to the crashing URL so you can reload and
try again.
This a huge step forward for OOPWV since it now has a feature that IPWV
can never replicate. :^)