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)

this._currentScaleValue = newValue.toString();
    if (isSameScale(this._currentScale, newScale)) {
      if (preset) {
        this.eventBus.dispatch("scalechanging", {
          source: this,
          scale: newScale,
          presetValue: newValue,
        });
      }
      return;
    }
    for (let i = 0, ii = this._pages.length; i < ii; i++) {
      this._pages[i].update(newScale);
    }
    this._currentScale = newScale;
    if (!noScroll) {
      let page = this._currentPageNumber,
        dest;
      if (
        this._location &&
        !(this.isInPresentationMode || this.isChangingPresentationMode)
      ) {
        page = this._location.pageNumber;
        dest = [
          null,
          { name: "XYZ" },
          this._location.left,
          this._location.top,
          null,
        ];