Make stylesheet owner node a reference instead of pointer.

third_party/WebKit/Source/core/css/CSSStyleSheet.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 31 matching lines @@
 
 enum StyleSheetUpdateType {
     PartialRuleUpdate,
     EntireStyleSheetUpdate
 };
 
 class CORE_EXPORT CSSStyleSheet final : public StyleSheet {
     DEFINE_WRAPPERTYPEINFO();
     WTF_MAKE_NONCOPYABLE(CSSStyleSheet);
 public:
-    static CSSStyleSheet* create(StyleSheetContents*, CSSImportRule* ownerRule = 0);
-    static CSSStyleSheet* create(StyleSheetContents*, Node* ownerNode);
-    static CSSStyleSheet* createInline(Node*, const KURL&, const TextPosition& startPosition = TextPosition::minimumPosition(), const String& encoding = String());
-    static CSSStyleSheet* createInline(StyleSheetContents*, Node* ownerNode, const TextPosition& startPosition = TextPosition::minimumPosition());
+    static CSSStyleSheet* create(StyleSheetContents*, CSSImportRule* ownerRule = nullptr);
+    static CSSStyleSheet* create(StyleSheetContents*, Node& ownerNode);
+    static CSSStyleSheet* createInline(Node&, const KURL&, const TextPosition& startPosition = TextPosition::minimumPosition(), const String& encoding = String());
+    static CSSStyleSheet* createInline(StyleSheetContents*, Node& ownerNode, const TextPosition& startPosition = TextPosition::minimumPosition());
 
     ~CSSStyleSheet() override;
 
     CSSStyleSheet* parentStyleSheet() const override;
     Node* ownerNode() const override { return m_ownerNode; }
     MediaList* media() const override;
     String href() const override;
     String title() const override { return m_title; }
     bool disabled() const override { return m_isDisabled; }
     void setDisabled(bool) override;
@@ skipping 50 matching lines @@
 
     bool sheetLoaded();
     bool loadCompleted() const { return m_loadCompleted; }
     void startLoadingDynamicSheet();
     void setText(const String&);
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     CSSStyleSheet(StyleSheetContents*, CSSImportRule* ownerRule);
-    CSSStyleSheet(StyleSheetContents*, Node* ownerNode, bool isInlineStylesheet, const TextPosition& startPosition);
+    CSSStyleSheet(StyleSheetContents*, Node& ownerNode, bool isInlineStylesheet, const TextPosition& startPosition);
 
     bool isCSSStyleSheet() const override { return true; }
     String type() const override { return "text/css"; }
 
     void reattachChildRuleCSSOMWrappers();
 
     bool canAccessRules() const;
 
     void setLoadCompleted(bool);
 
@@ skipping 33 matching lines @@
 {
     if (m_styleSheet)
         m_styleSheet->didMutateRules();
 }
 
 DEFINE_TYPE_CASTS(CSSStyleSheet, StyleSheet, sheet, sheet->isCSSStyleSheet(), sheet.isCSSStyleSheet());
 
 } // namespace blink
 
 #endif