Make RenderObject::style() return a const object

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index b7bec3653743d720fcc6d4402d14900e173d35a9..ab801aa1224dfba115d56b577d7f3f7dcce34058 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -268,7 +268,7 @@ public:
     //////////////////////////////////////////
     virtual bool canHaveChildren() const { return virtualChildren(); }
     virtual bool canHaveGeneratedChildren() const;
-    virtual bool isChildAllowed(RenderObject*, RenderStyle*) const { return true; }
+    virtual bool isChildAllowed(RenderObject*, const RenderStyle*) const { return true; }
     virtual void addChild(RenderObject* newChild, RenderObject* beforeChild = 0);
     virtual void addChildIgnoringContinuation(RenderObject* newChild, RenderObject* beforeChild = 0) { return addChild(newChild, beforeChild); }
     virtual void removeChild(RenderObject*);
@@ -321,7 +321,7 @@ public:
     void showRenderTreeAndMark(const RenderObject* markedObject1 = 0, const char* markedLabel1 = 0, const RenderObject* markedObject2 = 0, const char* markedLabel2 = 0, int depth = 0) const;
 #endif
 
-    static RenderObject* createObject(Element*, RenderStyle*);
+    static RenderObject* createObject(Element*, const RenderStyle*);
     static unsigned instanceCount() { return s_instanceCount; }
 
 #if !ENABLE(OILPAN)
@@ -603,8 +603,8 @@ public:
 
     // The pseudo element style can be cached or uncached.  Use the cached method if the pseudo element doesn't respect
     // any pseudo classes (and therefore has no concept of changing state).
-    RenderStyle* getCachedPseudoStyle(PseudoId, RenderStyle* parentStyle = 0) const;
-    PassRefPtr<RenderStyle> getUncachedPseudoStyle(const PseudoStyleRequest&, RenderStyle* parentStyle = 0, RenderStyle* ownStyle = 0) const;
+    RenderStyle* getCachedPseudoStyle(PseudoId, const RenderStyle* parentStyle = 0) const;
+    PassRefPtr<RenderStyle> getUncachedPseudoStyle(const PseudoStyleRequest&, const RenderStyle* parentStyle = 0, const RenderStyle* ownStyle = 0) const;
 
     virtual void updateDragState(bool dragOn);
 
@@ -796,11 +796,12 @@ public:
     virtual LayoutUnit minPreferredLogicalWidth() const { return 0; }
     virtual LayoutUnit maxPreferredLogicalWidth() const { return 0; }
 
-    RenderStyle* style() const { return m_style.get(); }
+    const RenderStyle* style() const { return m_style.get(); }
+    RenderStyle* deprecatedMutableStyle() const { return m_style.get(); }
 
     /* The two following methods are inlined in RenderObjectInlines.h */
-    RenderStyle* firstLineStyle() const;
-    RenderStyle* style(bool firstLine) const;
+    const RenderStyle* firstLineStyle() const;
+    const RenderStyle* style(bool firstLine) const;
 
     static inline Color resolveColor(const RenderStyle* styleToUse, int colorProperty)
     {