Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderTableCaption.h

Index: Source/core/rendering/RenderTableCaption.h
diff --git a/Source/core/rendering/RenderTableCaption.h b/Source/core/rendering/RenderTableCaption.h
index 711bbb79fe0725b772b0ef7d155bfe6b77c22a37..35755a9d03b26632206ecc341a7ff7cb53b11a12 100644
--- a/Source/core/rendering/RenderTableCaption.h
+++ b/Source/core/rendering/RenderTableCaption.h
@@ -43,20 +43,7 @@ private:
     RenderTable* table() const;
 };
 
-inline RenderTableCaption* toRenderTableCaption(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isTableCaption());
-    return static_cast<RenderTableCaption*>(object);
-}
-
-inline const RenderTableCaption* toRenderTableCaption(const RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isTableCaption());
-    return static_cast<const RenderTableCaption*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderTableCaption(const RenderTableCaption*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderTableCaption, isTableCaption());
 
 } // namespace WebCore