StyleBuilder should not know about StyleResolver.

Source/core/css/resolver/StyleResolverState.h

Index: Source/core/css/resolver/StyleResolverState.h
diff --git a/Source/core/css/resolver/StyleResolverState.h b/Source/core/css/resolver/StyleResolverState.h
index c484bf59f0f1baaf49c6d6d8d91e3fa6b70613e5..f414c21963b950a852f7792f21f9c4d7a30c2c35 100644
--- a/Source/core/css/resolver/StyleResolverState.h
+++ b/Source/core/css/resolver/StyleResolverState.h
@@ -42,11 +42,13 @@ class RenderRegion;
 class StyleResolverState {
 WTF_MAKE_NONCOPYABLE(StyleResolverState);
 public:
-    StyleResolverState(const Document*, Element*, RenderStyle* parentStyle = 0, RenderRegion* regionForStyling = 0);
+    StyleResolverState(Document*, Element*, RenderStyle* parentStyle = 0, RenderRegion* regionForStyling = 0);
     ~StyleResolverState();
 
+    // In FontLoader 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.
-    Document* document() const { return m_elementContext.document(); }
     Element* element() const { return m_elementContext.element(); }
     const ContainerNode* parentNode() const { return m_elementContext.parentNode(); }
     const RenderStyle* rootElementStyle() const { return m_elementContext.rootElementStyle(); }
@@ -124,6 +126,7 @@ private:
 
     void initElement(Element*);
 
+    Document* m_document;
     ElementResolveContext m_elementContext;
 
     // m_style is the primary output for each element's style resolve.