* @param {Canvas} element The <canvas> DOM element on which to draw.
* @param {CanvasRenderingContext2D} elementContext The drawing context.
* @param {DygraphLayout} layout The chart's DygraphLayout object.
* @param {Canvas} element The <canvas> DOM element on which to draw.
* @param {CanvasRenderingContext2D} elementContext The drawing context.
* @param {DygraphLayout} layout The chart's DygraphLayout object.