resources/sksl/shared/Derivatives.sksl - skia - Git at Google

 /*#pragma settings ShaderDerivativeExtensionString*/

 void main() {
     sk_FragColor.x = half(dFdx(1));
 }
	/#pragma settings ShaderDerivativeExtensionString/

	void main() {
	sk_FragColor.x = half(dFdx(1));
	}