Fix bad cast to XPath::Filter in XPathGrammar.y

Source/core/xml/XPathPath.cpp

Index: Source/core/xml/XPathPath.cpp
diff --git a/Source/core/xml/XPathPath.cpp b/Source/core/xml/XPathPath.cpp
index dbc25506bc0f6d46d18711990aba56669a8ca06d..80e57b3d49ee756ea68ca44dcd0342943e5f8ada 100644
--- a/Source/core/xml/XPathPath.cpp
+++ b/Source/core/xml/XPathPath.cpp
@@ -185,7 +185,7 @@ void LocationPath::insertFirstStep(Step* step)
     m_steps.insert(0, step);
 }
 
-Path::Path(Filter* filter, LocationPath* path)
+Path::Path(Expression* filter, LocationPath* path)
     : m_filter(filter)
     , m_path(path)
 {