Use JSON imports instead of PDFJSDev.json

JSON imports are now supported by all tools used in PDF.js' build
process. The `chromecom.js` file is bundled by webpack and
import attributes are thus removed, so browser compatibility for this
new syntax is not relevant.

external/builder/babel-plugin-pdfjs-preprocessor.mjs

@@ -1,10 +1,7 @@
 import { types as t, transformSync } from "@babel/core";
-import fs from "fs";
-import { join as joinPaths } from "path";
 import vm from "vm";
 
 const PDFJS_PREPROCESSOR_NAME = "PDFJSDev";
-const ROOT_PREFIX = "$ROOT/";
 
 function isPDFJSPreprocessor(obj) {
   return obj.type === "Identifier" && obj.name === PDFJS_PREPROCESSOR_NAME;
@@ -40,18 +37,6 @@ function handlePreprocessorAction(ctx, actionName, args, path) {
           return result;
         }
         break;
-      case "json":
-        if (!t.isStringLiteral(arg)) {
-          throw new Error("Path to JSON is not provided");
-        }
-        let jsonPath = arg.value;
-        if (jsonPath.startsWith(ROOT_PREFIX)) {
-          jsonPath = joinPaths(
-            ctx.rootPath,
-            jsonPath.substring(ROOT_PREFIX.length)
-          );
-        }
-        return JSON.parse(fs.readFileSync(jsonPath, "utf8"));
     }
     throw new Error("Unsupported action");
   } catch (e) {

external/builder/fixtures_babel/evals-expected.js

@@ -10,9 +10,6 @@ var g = {
   },
   j: 2
 };
-var h = {
-  test: "test"
-};
 var i = '0';
 var j = {
   i: 1

external/builder/fixtures_babel/evals.js

@@ -5,7 +5,6 @@ var d = PDFJSDev.test('FALSE');
 var e = PDFJSDev.eval('TRUE');
 var f = PDFJSDev.eval('TEXT');
 var g = PDFJSDev.eval('OBJ');
-var h = PDFJSDev.json('$ROOT/external/builder/fixtures_babel/evals.json');
 var i = typeof PDFJSDev === 'undefined' ? PDFJSDev.eval('FALSE') : '0';
 var j = typeof PDFJSDev !== 'undefined' ? PDFJSDev.eval('OBJ.obj') : '0';
 var k = !PDFJSDev.test('TRUE');

external/builder/fixtures_babel/evals.json

@@ -1 +0,0 @@
-{ "test": "test" }