Improve RAII of StyleResolverState.

Source/core/css/resolver/StyleResolverState.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 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 27 matching lines @@
 
 namespace blink {
 
 class CSSAnimationUpdate;
 class FontDescription;
 
 class StyleResolverState {
     STACK_ALLOCATED();
     WTF_MAKE_NONCOPYABLE(StyleResolverState);
 public:
-    StyleResolverState(Document&, Element*, RenderStyle* parentStyle = 0);
+    StyleResolverState(Document&, const ElementResolveContext&, PassRefPtr<RenderStyle>, PassRefPtr<RenderStyle> parentStyle);
+    StyleResolverState(Document&, Element*, PassRefPtr<RenderStyle>, RenderStyle* parentStyle = nullptr);

[rune, 2014/11/13 14:28:43]

How about making the parentStyle parameter mandatory non-null? It needs to be
non-null after construction regardlessly, and I think the logic for which parent
style to use in that case should be decided by the caller.

     ~StyleResolverState();
 
     // In FontFaceSet and CanvasRenderingContext2D, we don't have an element to grab the document from.
     // This is why we have to store the document separately.
     Document& document() const { return *m_document; }
     // These are all just pass-through methods to ElementResolveContext.
     Element* element() const { return m_elementContext.element(); }
     const ContainerNode* parentNode() const { return m_elementContext.parentNode(); }
     const RenderStyle* rootElementStyle() const { return m_elementContext.rootElementStyle(); }
     EInsideLink elementLinkState() const { return m_elementContext.elementLinkState(); }
     bool distributedToInsertionPoint() const { return m_elementContext.distributedToInsertionPoint(); }
 
     const ElementResolveContext& elementContext() const { return m_elementContext; }
 
-    void setStyle(PassRefPtr<RenderStyle> style)
-    {
-        m_style = style;
-        m_cssToLengthConversionData.setStyle(m_style.get());
-        m_fontBuilder.setStyle(m_style.get());
-    }
     const RenderStyle* style() const { return m_style.get(); }
     RenderStyle* style() { return m_style.get(); }
     PassRefPtr<RenderStyle> takeStyle() { return m_style.release(); }
 
     const CSSToLengthConversionData& cssToLengthConversionData() const { return m_cssToLengthConversionData; }
 
     void setAnimationUpdate(PassOwnPtrWillBeRawPtr<CSSAnimationUpdate>);
     const CSSAnimationUpdate* animationUpdate() { return m_animationUpdate.get(); }
     PassOwnPtrWillBeRawPtr<CSSAnimationUpdate> takeAnimationUpdate();
 
-    void setParentStyle(PassRefPtr<RenderStyle> parentStyle) { m_parentStyle = parentStyle; }
     const RenderStyle* parentStyle() const { return m_parentStyle.get(); }
     RenderStyle* parentStyle() { return m_parentStyle.get(); }
 
     // FIXME: These are effectively side-channel "out parameters" for the various
     // map functions. When we map from CSS to style objects we use this state object
     // to track various meta-data about that mapping (e.g. if it's cache-able).
     // We need to move this data off of StyleResolverState and closer to the
     // objects it applies to. Possibly separating (immutable) inputs from (mutable) outputs.
     void setApplyPropertyToRegularStyle(bool isApply) { m_applyPropertyToRegularStyle = isApply; }
     void setApplyPropertyToVisitedLinkStyle(bool isApply) { m_applyPropertyToVisitedLinkStyle = isApply; }
@@ skipping 67 matching lines @@
     ElementStyleResources m_elementStyleResources;
     // CSSToStyleMap is a pure-logic class and only contains
     // a back-pointer to this object.
     CSSToStyleMap m_styleMap;
     Vector<AtomicString> m_contentAttrValues;
 };
 
 } // namespace blink
 
 #endif // StyleResolverState_h