Move Parser creation to its own function (issue #849).

This is the first step to implement innerHTML, as we need a way
create and initialize a parser object while setting the received
DOMString (which may be either text/html/whatever).

src/components/script/html/hubbub_html_parser.rs

@@ -328,13 +328,9 @@ pub fn parse_html(page: &Page,
         *page.mut_url() = Some((base_url.clone(), true));
     }
 
-    let mut parser = hubbub::Parser("UTF-8", false);
+    let mut parser = build_parser(unsafe { document.to_hubbub_node() });
     debug!("created parser");
 
-    parser.set_document_node(unsafe { document.to_hubbub_node() });
-    parser.enable_scripting(true);
-    parser.enable_styling(true);
-
     let (css_chan2, js_chan2) = (css_chan.clone(), js_chan.clone());
 
     let doc_cell = RefCell::new(document);
@@ -557,3 +553,11 @@ pub fn parse_html(page: &Page,
     }
 }
 
+fn build_parser(node: hubbub::NodeDataPtr) -> hubbub::Parser {
+    let mut parser = hubbub::Parser("UTF-8", false);
+    parser.set_document_node(node);
+    parser.enable_scripting(true);
+    parser.enable_styling(true);
+    return parser
+}
+