anchor.diff:      var mapPath = '$jsPath.map';
       await Directory(jsDir).create();
       var jsCode = jsProgramToCode(jsModule, format,
  -        jsUrl: jsPath, mapUrl: mapPath, buildSourceMap: true);
  +        jsUrl: jsPath,
  +        mapUrl: mapPath,
  +        buildSourceMap: true,
  +        customScheme: customScheme);
       await File(jsPath).writeAsString(jsCode.code);
       await File(mapPath).writeAsString(json.encode(jsCode.sourceMap));
     }
  
positive.code:     }
    }
  
    var options = CompilerOptions()
      ..compileSdk = true
      // TODO(sigmund): remove these two unnecessary options when possible.
      ..sdkRoot = Uri.base
      ..packagesFileUri = Uri.base.resolveUri(Uri.file(packagesPath))
      ..librariesSpecificationUri = Uri.base.resolveUri(Uri.file(librarySpecPath))
      ..target = target
      ..onDiagnostic = onDiagnostic
      ..environmentDefines = {};
  
    var inputs = target.extraRequiredLibraries.map(Uri.parse).toList();
    var compilerResult = await kernelForModule(inputs, options);
    var component = compilerResult.component;
  
  
negative.code: import 'package:front_end/src/api_unstable/ddc.dart'
      show
          CompilerOptions,
          DiagnosticMessage,
          Severity,
          StandardFileSystem,
          kernelForModule,
          printDiagnosticMessage;
  import 'package:kernel/kernel.dart';
  import 'package:kernel/target/targets.dart';
  import 'package:path/path.dart' as p;
  