CSS properties fontFamily and fontSize are part of @html_dom_node now,
and the TrueType API only accepts I32 code point streams, so we have
to preprocess UTF-8 streams before rendering text.
Until we have a default style sheet implemented, set the default colors
to black text on white background for the root node, so that we don't
end up with unreadable black bars everywhere.
We match the following address bar behavior from Chrome and Firefox:
- When the address bar is clicked, select all text on mouse up if no
selection currently exists.
- On address bar blur, clear the selection.
