src/Pure/Thy/document_build.scala

         val content = YXML.parse_body(entry.text)
         File.content(path, content)
       }
 
     lazy val session_graph: File.Content = {
-      val path = Presentation.session_graph_path
+      val path = Browser_Info.session_graph_path
       val content = graphview.Graph_File.make_pdf(options, base.session_graph_display)
       File.content(path, content)
     }
 
     lazy val session_tex: File.Content = {