message: parametized draw method
diff: @@ -14,10 +14,10 @@ import DecodeHintType from '../core/DecodeHintType';
  * @class BrowserCodeReader
  */
  export default class BrowserCodeReader {
  - protected videoElement: HTMLVideoElement;
  - protected imageElement: HTMLImageElement;
  - protected canvasElementContext: CanvasRenderingContext2D;
  + private videoElement: HTMLVideoElement;
  + private imageElement: HTMLImageElement;
  private canvasElement: HTMLCanvasElement;
  + private canvasElementContext: CanvasRenderingContext2D;
  private timeoutHandler: number;
  private stream: MediaStream;
  private videoPlayEndedEventListener: EventListener;
  @@ -264,8 +264,11 @@ export default class BrowserCodeReader {
  }
  }
  - protected drawImageOnCanvas() {
  - this.canvasElementContext.drawImage(this.videoElement || this.imageElement, 0, 0);
  + /**
  + * This will remain protected, so who extends this class can customize this method.
  + */
  + protected drawImageOnCanvas(canvasElementContext: CanvasRenderingContext2D, srcElement: HTMLVideoElement | HTMLImageElement) {
  + canvasElementContext.drawImage(srcElement, 0, 0);
  }
  protected readerDecode(binaryBitmap: BinaryBitmap): Result {
  