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)

return this.messageHandler.sendWithPromise("GetMarkInfo", null);
  }
  getStats() {
    return this.messageHandler.sendWithPromise("GetStats", null);
  }
  async startCleanup(keepLoadedFonts = false) {
    await this.messageHandler.sendWithPromise("Cleanup", null);
    if (this.destroyed) {
      return; 
    }
    for (let i = 0, ii = this.pageCache.length; i < ii; i++) {
      const page = this.pageCache[i];
      if (!page) {
        continue;
      }
      const cleanupSuccessful = page.cleanup();
      if (!cleanupSuccessful) {
        throw new Error(`startCleanup: Page ${i + 1} is currently rendering.`);
      }
    }
    this.commonObjs.clear();
    if (!keepLoadedFonts) {
      this.fontLoader.clear();
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    this._hasJSActionsPromise = null;
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  get loadingParams() {