The map on http://maps.google.com/ does not render, but appears white. This was noticed last weekend (around the 8th of July) and it seems that this was not caused by a regression in the code but rather possibly a change in the website. I have tested with revisions between r24012 and r24112 and they all exhibit this issue.
I should note that this issue is probably specific to the Gdk/Cairo build, unless other ports can confirm the issue.
I see a map when going to http://maps.google.com/, so this only affects the Gdk/Cairo build. Used a local debug build of WebKit r24108 with Safari 3.0 (522.12) on Mac OS X 10.4.10 (8R218).
maps.google.com introduced iframe's for the map. Nowadays WebKit/Gtk+ supports multiple frames.