The prebuilt files include `web/pdf_viewer.js` with some viewer APIs. Those are missing from type declarations.
* limitations under the License.
 */
"use strict";
const autoprefixer = require("autoprefixer");
const calc = require("postcss-calc");
const fs = require("fs");
const gulp = require("gulp");
const postcss = require("gulp-postcss");
const rename = require("gulp-rename");
const replace = require("gulp-replace");
const mkdirp = require("mkdirp");
const path = require("path");
const rimraf = require("rimraf");
const stream = require("stream");
const exec = require("child_process").exec;
const spawn = require("child_process").spawn;
const spawnSync = require("child_process").spawnSync;
const streamqueue = require("streamqueue");
const merge = require("merge-stream");
const zip = require("gulp-zip");
const webpack2 = require("webpack");
const webpackStream = require("webpack-stream");
const Vinyl = require("vinyl");
const vfs = require("vinyl-fs");
const through = require("through2");
const BUILD_DIR = "build/";
const L10N_DIR = "l10n/";
const TEST_DIR = "test/";
const EXTENSION_SRC_DIR = "extensions/";
const BASELINE_DIR = BUILD_DIR + "baseline/";