Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderRegion.h

Index: Source/core/rendering/RenderRegion.h
diff --git a/Source/core/rendering/RenderRegion.h b/Source/core/rendering/RenderRegion.h
index 2d9988d76d6c5e3c0235fe899e738ae4dec5da84..1fa5de510e6d31775ac2e456dff768444cb7d1c4 100644
--- a/Source/core/rendering/RenderRegion.h
+++ b/Source/core/rendering/RenderRegion.h
@@ -216,20 +216,7 @@ private:
     bool m_hasAutoLogicalHeight : 1;
 };
 
-inline RenderRegion* toRenderRegion(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderRegion());
-    return static_cast<RenderRegion*>(object);
-}
-
-inline const RenderRegion* toRenderRegion(const RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderRegion());
-    return static_cast<const RenderRegion*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderRegion(const RenderRegion*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderRegion, isRenderRegion());
 
 } // namespace WebCore