I was wondering if WebGL is considered stable enough to be enabled by default. It makes some PDFs render much faster and it has been off by default for a while now, so we have had quite some time to test it.

If we decide to enable WebGL by default, we should not forget to update https://github.com/mozilla/pdf.js/blob/master/extensions/chromium/preferences_schema.json#L39 as well.

/cc @yurydelendik 
/cc @Snuffleupagus (because IIRC you were testing WebGL too)

if (data[pos - lineSize] !== data[pos]) {
      points[j0 + j] = data[pos] ? 2 : 4;
      ++count;
    }
    if (count > POINT_TO_PROCESS_LIMIT) {
      return null;
    }
  }
  pos = lineSize * (height - 1);
  j0 = i * width1;
  if (data[pos] !== 0) {
    points[j0] = 8;
    ++count;
  }
  for (j = 1; j < width; j++) {
    if (data[pos] !== data[pos + 1]) {
      points[j0 + j] = data[pos] ? 4 : 8;
      ++count;
    }
    pos++;
  }
  if (data[pos] !== 0) {
    points[j0 + j] = 4;
    ++count;
  }
  if (count > POINT_TO_PROCESS_LIMIT) {
    return null;
  }
  
  const steps = new Int32Array([0, width1, -1, 0, -width1, 0, 0, 0, 1]);