added toString methods

lib/hooks/hooks-frame.js

@@ -152,6 +152,7 @@ this.hooksFrame = this.hooksFrame || (() => {
 				return id;
 			}
 		};
+		window.requestAnimationFrame.toString = function () { return "requestAnimationFrame() { [native code] }"; };
 
 		window.cancelAnimationFrame = function (id) {
 			pendingRequestAnimationFrameCalls.delete(id);
@@ -161,6 +162,7 @@ this.hooksFrame = this.hooksFrame || (() => {
 				return cancelAnimationFrame(id);
 			}
 		};
+		window.cancelAnimationFrame.toString = function () { return "cancelAnimationFrame() { [native code] }"; };
 
 		const FontFace = window.FontFace;
 		let warningFontFaceDisplayed;