Safari starts a new web process when the user enters a new URI in the address bar. The point of this is to reduce memory usage in the event of memory leaks. We should probably consider doing this too. (Of course, the WKView/WebKitWebView stays the same.)
In http://stackoverflow.com/questions/33990687/webkitgtk-about-webkit-web-view-load-uri/34572803 I offer terrible workarounds to a user who's suffering from memory leaks in his application. If webkit_web_view_load_* were to start a new web process, this would not be an issue. IIRC this approach was suggested to me by Dan Bates, Alex Christensen, and Ryosuke at the Contributors Meeting. One issue is we would have to figure out how this would interact with webkit_web_view_new_with_related_view. I think that once you load a second URI, it's logical that the view would simply cease to be related and use a new web process.
Obsoleted by PSON.