PictureInPicture Volume Control

-------------------------------------
-------------------------------------
Additions marked with /*NEW*/

IN modules\ActorManagerParent.jsm
-------------------------------------
-------------------------------------
.
...
  PictureInPicture: {
    child: {
      module: "resource://gre/actors/PictureInPictureChild.jsm",
      events: {
        "MozTogglePictureInPicture": {capture: true},
      },

      messages: [
        "PictureInPicture:SetupPlayer",
        "PictureInPicture:Play",
        "PictureInPicture:Pause",
        "PictureInPicture:Volume",/*NEW*/
        "PictureInPicture:VolumeUp",/*NEW*/
      ],
    },
  },
....
..
-------------------------------------
-------------------------------------
IN actors\PictureInPictureChild.jsm
-------------------------------------
-------------------------------------
..
...
  receiveMessage(message) {
    switch (message.name) {
      case "PictureInPicture:SetupPlayer": {
        this.setupPlayer();
        break;
      }
      case "PictureInPicture:Play": {
        this.play();
        break;
      }
      case "PictureInPicture:Pause": {
        this.pause();
        break;
      }
      case "PictureInPicture:Volume": { /*NEW*/
        this.volume();
        break;
      }
      case "PictureInPicture:VolumeUp": { /*NEW*/
        this.volume2();
        break;
      }
    }
  }
  ....
  ..
  play() {
    let video = this.weakVideo;
    if (video) {
      video.play();
    }
  }
  /*NEW FUNCTION*/
    volume() {

    let video = this.weakVideo;
    let currVol = video.volume;
    let actualChange = 4 / 100;

    currVol -= actualChange;

    if (currVol > 1) currVol = 1;
    else if (currVol < 0) currVol = 0;
    video.volume = currVol;
    }

    /*NEW FUNCTION*/
    volume2() {
    let video = this.weakVideo;
    let currVol = video.volume;
    let actualChange = 4 / 100;

    currVol += actualChange;

    if (currVol > 1) currVol = 1;
    else if (currVol < 0) currVol = 0;
    video.volume = currVol;
    }
...
..
 -------------------------------------
-------------------------------------
IN actors\PictureInPictureChild.jsm
-------------------------------------
-------------------------------------

..
...
  document.getElementById("pause").addEventListener("click", () => {
    mm.sendAsyncMessage("PictureInPicture:Pause");
  });

   /*NEW FUNCTION*/
  document.getElementById("pause").addEventListener("wheel", function(e) {
  if (e.deltaY < 0) {
     mm.sendAsyncMessage("PictureInPicture:VolumeUp");
  }
  if (e.deltaY > 0) {
     mm.sendAsyncMessage("PictureInPicture:Volume");
  }
  ...
  ..