src/vs/editor/browser/viewParts/minimap/minimap.ts/InnerMinimap/renderDecoration
class InnerMinimap:	private renderDecoration(canvasContext: CanvasRenderingContext2D, decorationColor: Color | undefined, x: number, y: number, width: number, height: number) {
		canvasContext.fillStyle = decorationColor && decorationColor.toString() || '';
		canvasContext.fillRect(x, y, width, height);
	}