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)

/* Copyright 2014 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { shadow } from "../shared/util.js";
class WebGLContext {
  constructor({ enable = false }) {
    this._enabled = enable === true;
  }
  get isEnabled() {
    let enabled = this._enabled;
    if (enabled) {
      enabled = WebGLUtils.tryInitGL();
    }
    return shadow(this, "isEnabled", enabled);
  }
  composeSMask({ layer, mask, properties }) {
    return WebGLUtils.composeSMask(layer, mask, properties);
  }
  drawFigures({ width, height, backgroundColor, figures, context }) {