TypeError: The CanvasRenderingContext2D.webkitBackingStorePixelRatio getter can only be used on instances of CanvasRenderingContext2D
ios10:
CanvasRenderingContext2D.prototype.webkitBackingStorePixelRatio 报异常
ios10:
CanvasRenderingContext2D.prototype.webkitBackingStorePixelRatio 报异常