Make RenderObject::style() return a const object

Source/core/css/resolver/StyleAdjuster.h

Index: Source/core/css/resolver/StyleAdjuster.h
diff --git a/Source/core/css/resolver/StyleAdjuster.h b/Source/core/css/resolver/StyleAdjuster.h
index d578ba2a9f730b9d0b20b902a50358588ed6b1d9..d76a803ee26aed99daa056593eb9bb6efa1ce40e 100644
--- a/Source/core/css/resolver/StyleAdjuster.h
+++ b/Source/core/css/resolver/StyleAdjuster.h
@@ -41,12 +41,12 @@ public:
         : m_useQuirksModeStyles(useQuirksModeStyles)
     { }
 
-    void adjustRenderStyle(RenderStyle* styleToAdjust, RenderStyle* parentStyle, Element*, const CachedUAStyle*);
+    void adjustRenderStyle(RenderStyle* styleToAdjust, const RenderStyle* parentStyle, Element*, const CachedUAStyle*);
 
 private:
     void adjustStyleForFirstLetter(RenderStyle*);
-    void adjustStyleForDisplay(RenderStyle* styleToAdjust, RenderStyle* parentStyle);
-    void adjustStyleForHTMLElement(RenderStyle* styleToAdjust, RenderStyle* parentStyle, HTMLElement&);
+    void adjustStyleForDisplay(RenderStyle* styleToAdjust, const RenderStyle* parentStyle);
+    void adjustStyleForHTMLElement(RenderStyle* styleToAdjust, const RenderStyle* parentStyle, HTMLElement&);
     void adjustOverflow(RenderStyle* styleToAdjust);
     void adjustStyleForAlignment(RenderStyle& styleToAdjust, const RenderStyle& parentStyle);