The following layout test is crashing on GTK since r169017 <http://trac.webkit.org/changeset/169017>

fast/dom/NavigatorContentUtils/register-protocol-handler.html

The relevant part of the GDB backtrace is:

Core was generated by `/home/clopez/webkit/webkit/WebKitBuild/Release/bin/WebKitWebProcess 12'.
Program terminated with signal 11, Segmentation fault.
#0  0x00007f4543f26f44 in WebCore::NavigatorContentUtils::registerProtocolHandler(WebCore::Navigator*, WTF::String const&, WTF::String const&, WTF::String const&, int&) ()
   from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit2gtk-3.0.so.25
[....]
Thread 1 (Thread 0x7f45361e9a00 (LWP 14338)):
#0  0x00007f4543f26f44 in WebCore::NavigatorContentUtils::registerProtocolHandler(WebCore::Navigator*, WTF::String const&, WTF::String const&, WTF::String const&, int&) () $
#1  0x00007f4544ecf31b in WebCore::jsNavigatorPrototypeFunctionRegisterProtocolHandler(JSC::ExecState*) () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libwebkit$
#2  0x00007f44f4c420b4 in ?? ()
#3  0x00007fff16ae6420 in ?? ()
#4  0x00007f45463924c8 in llint_entry () from /home/clopez/webkit/webkit/WebKitBuild/Release/lib/libjavascriptcoregtk-3.0.so.0