Set webextension icon color

setIconColor.js

/** Too slowwww **/
const setIconColor = function(){
  let img = new Image();
  img.src = "icons/binoculars_white.png";
  img.onload = function() {
      var canvas = document.createElement("canvas");
      var ctx = canvas.getContext("2d");      
      ctx.drawImage(img, 0, 0);
      ctx.globalCompositeOperation = "source-in";
      ctx.fillStyle = "#09f"; //any color
      ctx.fillRect(0, 0, 64, 64);
      let imageData = ctx.getImageData(0, 0, 64, 64);     
      browser.browserAction.setIcon({imageData: imageData});
  }
}