WebContext is a construct only property of WebKitWebView. webkit_web_view_new() passes the default web context as g_object_new parameter. If a web view is created with g_object_new without passing the web context parameter (which is a normal situation when creating objects derived from WebKitWebView), the default value for GObject propetrties is set (NULL). In webkitWebViewConstructed we assume the view already has a web context and it crashes if it hasn't.
Created attachment 126060 [details] Patch
Thanks for the patch. If this patch contains new public API please make sure it follows the guidelines for new WebKit2 GTK+ API. See http://trac.webkit.org/wiki/WebKitGTK/AddingNewWebKit2API
Committed r107092: <http://trac.webkit.org/changeset/107092>