Convert DocumentParser code to Use more reference

Source/core/html/parser/HTMLDocumentParser.h

Index: Source/core/html/parser/HTMLDocumentParser.h
diff --git a/Source/core/html/parser/HTMLDocumentParser.h b/Source/core/html/parser/HTMLDocumentParser.h
index b07a16c4f209de0a31973134db7269a86209088e..e0bdc2c100ce4593c0f43586e56e1a8c2f65755a 100644
--- a/Source/core/html/parser/HTMLDocumentParser.h
+++ b/Source/core/html/parser/HTMLDocumentParser.h
@@ -68,7 +68,7 @@ class PumpSession;
 class HTMLDocumentParser :  public ScriptableDocumentParser, HTMLScriptRunnerHost, ResourceClient {
     WTF_MAKE_FAST_ALLOCATED;
 public:
-    static PassRefPtr<HTMLDocumentParser> create(HTMLDocument* document, bool reportErrors)
+    static PassRefPtr<HTMLDocumentParser> create(HTMLDocument& document, bool reportErrors)
     {
         return adoptRef(new HTMLDocumentParser(document, reportErrors));
     }
@@ -110,7 +110,7 @@ protected:
     virtual void append(PassRefPtr<StringImpl>) OVERRIDE;
     virtual void finish() OVERRIDE FINAL;
 
-    HTMLDocumentParser(HTMLDocument*, bool reportErrors);
+    HTMLDocumentParser(HTMLDocument&, bool reportErrors);
     HTMLDocumentParser(DocumentFragment*, Element* contextElement, ParserContentPolicy);
 
     HTMLTreeBuilder* treeBuilder() const { return m_treeBuilder.get(); }