Have Node::document() return a reference instead of a pointer

Source/core/html/parser/HTMLDocumentParser.cpp

Index: Source/core/html/parser/HTMLDocumentParser.cpp
diff --git a/Source/core/html/parser/HTMLDocumentParser.cpp b/Source/core/html/parser/HTMLDocumentParser.cpp
index cdc7e0ae615ac61b058e2f65565023568741f754..b5b283ec2f12702866b083d04aa5dcdb9806649d 100644
--- a/Source/core/html/parser/HTMLDocumentParser.cpp
+++ b/Source/core/html/parser/HTMLDocumentParser.cpp
@@ -95,12 +95,12 @@ HTMLDocumentParser::HTMLDocumentParser(Document* document, bool reportErrors)
 // FIXME: Member variables should be grouped into self-initializing structs to
 // minimize code duplication between these constructors.
 HTMLDocumentParser::HTMLDocumentParser(DocumentFragment* fragment, Element* contextElement, ParserContentPolicy parserContentPolicy)
-    : ScriptableDocumentParser(fragment->document(), parserContentPolicy)
-    , m_options(fragment->document())
+    : ScriptableDocumentParser(&fragment->document(), parserContentPolicy)
+    , m_options(&fragment->document())
     , m_token(adoptPtr(new HTMLToken))
     , m_tokenizer(HTMLTokenizer::create(m_options))
     , m_treeBuilder(HTMLTreeBuilder::create(this, fragment, contextElement, this->parserContentPolicy(), m_options))
-    , m_xssAuditorDelegate(fragment->document())
+    , m_xssAuditorDelegate(&fragment->document())
     , m_weakFactory(this)
     , m_isPinnedToMainThread(true)
     , m_endWasDelayed(false)