Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderVideo.h

Index: Source/core/rendering/RenderVideo.h
diff --git a/Source/core/rendering/RenderVideo.h b/Source/core/rendering/RenderVideo.h
index 03eeb2cf84f19816b51ec03c8e3a43a3d3b7c7d4..594fbc3218f072d919e9813690baccf36cb5bf11 100644
--- a/Source/core/rendering/RenderVideo.h
+++ b/Source/core/rendering/RenderVideo.h
@@ -79,20 +79,7 @@ private:
     LayoutSize m_cachedImageSize;
 };
 
-inline RenderVideo* toRenderVideo(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isVideo());
-    return static_cast<RenderVideo*>(object);
-}
-
-inline const RenderVideo* toRenderVideo(const RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isVideo());
-    return static_cast<const RenderVideo*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderVideo(const RenderVideo*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderVideo, isVideo());
 
 } // namespace WebCore