Have Element::ensureMutableInlineStyle() return a reference

Source/core/css/PropertySetCSSStyleDeclaration.h

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 54 matching lines @@
 
     virtual bool cssPropertyMatches(CSSPropertyID, const CSSValue*) const OVERRIDE FINAL;
     virtual PassRefPtr<MutableStylePropertySet> copyProperties() const OVERRIDE FINAL;
 
     CSSValue* cloneAndCacheForCSSOM(CSSValue*);
 
 protected:
     enum MutationType { NoChanges, PropertyChanged };
     virtual void willMutate() { }
     virtual void didMutate(MutationType) { }
-    virtual MutableStylePropertySet* propertySet() const = 0;
+    virtual MutableStylePropertySet& propertySet() const = 0;
 
     OwnPtrWillBePersistent<WillBeHeapHashMap<CSSValue*, RefPtrWillBeMember<CSSValue> > > m_cssomCSSValueClones;
 };
 
 class PropertySetCSSStyleDeclaration : public AbstractPropertySetCSSStyleDeclaration {
 public:
-    PropertySetCSSStyleDeclaration(MutableStylePropertySet* propertySet) : m_propertySet(propertySet) { }
+    PropertySetCSSStyleDeclaration(MutableStylePropertySet& propertySet) : m_propertySet(&propertySet) { }
 
     virtual void ref() OVERRIDE;
     virtual void deref() OVERRIDE;
 
 protected:
-    virtual MutableStylePropertySet* propertySet() const OVERRIDE FINAL { return m_propertySet; }
+    virtual MutableStylePropertySet& propertySet() const OVERRIDE FINAL { ASSERT(m_propertySet); return *m_propertySet; }
 
-    MutableStylePropertySet* m_propertySet;
+    MutableStylePropertySet* m_propertySet; // Cannot be null
 };
 
 class StyleRuleCSSStyleDeclaration FINAL : public PropertySetCSSStyleDeclaration
 {
 public:
-    static PassRefPtr<StyleRuleCSSStyleDeclaration> create(MutableStylePropertySet* propertySet, CSSRule* parentRule)
+    static PassRefPtr<StyleRuleCSSStyleDeclaration> create(MutableStylePropertySet& propertySet, CSSRule* parentRule)
     {
         return adoptRef(new StyleRuleCSSStyleDeclaration(propertySet, parentRule));
     }
 
     void clearParentRule() { m_parentRule = 0; }
 
     virtual void ref() OVERRIDE;
     virtual void deref() OVERRIDE;
 
-    void reattach(MutableStylePropertySet*);
+    void reattach(MutableStylePropertySet&);
 
 private:
-    StyleRuleCSSStyleDeclaration(MutableStylePropertySet*, CSSRule*);
+    StyleRuleCSSStyleDeclaration(MutableStylePropertySet&, CSSRule*);
     virtual ~StyleRuleCSSStyleDeclaration();
 
     virtual CSSStyleSheet* parentStyleSheet() const OVERRIDE;
 
     virtual CSSRule* parentRule() const OVERRIDE { return m_parentRule;  }
 
     virtual void willMutate() OVERRIDE;
     virtual void didMutate(MutationType) OVERRIDE;
 
     unsigned m_refCount;
     CSSRule* m_parentRule;
 };
 
 class InlineCSSStyleDeclaration FINAL : public AbstractPropertySetCSSStyleDeclaration
 {
 public:
     explicit InlineCSSStyleDeclaration(Element* parentElement)
         : m_parentElement(parentElement)
     {
     }
 
 private:
-    virtual MutableStylePropertySet* propertySet() const OVERRIDE;
+    virtual MutableStylePropertySet& propertySet() const OVERRIDE;
     virtual void ref() OVERRIDE;
     virtual void deref() OVERRIDE;
     virtual CSSStyleSheet* parentStyleSheet() const OVERRIDE;
     virtual Element* parentElement() const OVERRIDE { return m_parentElement; }
     virtual void clearParentElement() OVERRIDE { m_parentElement = 0; }
 
     virtual void didMutate(MutationType) OVERRIDE;
 
     Element* m_parentElement;
 };
 
 } // namespace WebCore
 
 #endif