Update more core classes to use OVERRIDE / FINAL when needed

Source/core/rendering/RenderBlock.h

Index: Source/core/rendering/RenderBlock.h
diff --git a/Source/core/rendering/RenderBlock.h b/Source/core/rendering/RenderBlock.h
index 1afbdd50c8a54e05a41e280ec55417e96db4f7a2..e0fde8f2cf794d38c09e5fb96c7281024b8b9865 100644
--- a/Source/core/rendering/RenderBlock.h
+++ b/Source/core/rendering/RenderBlock.h
@@ -104,8 +104,8 @@ public:
     // FIXME-BLOCKFLOW: Remove virtualizaion when all callers have moved to RenderBlockFlow
     virtual void deleteLineBoxTree();
 
-    virtual void addChild(RenderObject* newChild, RenderObject* beforeChild = 0);
-    virtual void removeChild(RenderObject*);
+    virtual void addChild(RenderObject* newChild, RenderObject* beforeChild = 0) OVERRIDE;
+    virtual void removeChild(RenderObject*) OVERRIDE;
 
     virtual void layoutBlock(bool relayoutChildren, LayoutUnit pageLogicalHeight = 0);
 
@@ -356,7 +356,7 @@ protected:
     virtual int inlineBlockBaseline(LineDirectionMode) const OVERRIDE;
     int lastLineBoxBaseline(LineDirectionMode) const;
 
-    virtual void updateHitTestResult(HitTestResult&, const LayoutPoint&);
+    virtual void updateHitTestResult(HitTestResult&, const LayoutPoint&) OVERRIDE;
 
     // Delay update scrollbar until finishDelayRepaint() will be
     // called. This function is used when a flexbox is laying out its