anchor.diff:          return new PrecompilerCompilerConfiguration(
               isDebug: isDebug,
               isChecked: isChecked,
  -            isProduct: isProduct,
               arch: configuration['arch']);
         case 'none':
           return new NoneCompilerConfiguration(
  
positive.code:       CommandBuilder commandBuilder,
        List arguments,
        Map<String, String> environmentOverrides) {
      var sourceDir = Directory.current.path;
      var exec = "$buildDir/gen_snapshot";
      var args = new List();
  
      var precompiledVMIsolate = "$tempDir/precompiled.vmisolate";
      var precompiledIsolate = "$tempDir/precompiled.isolate";
      var precompiledInstructions = "$tempDir/precompiled.S";
      var dartProductEntries = "$sourceDir/runtime/bin/dart_product_entries.txt";
      var dartEntries = "$sourceDir/runtime/bin/dart_entries.txt";
      var vmServiceIoMain = "$sourceDir/runtime/bin/vmservice/vmservice_io.dart";
  
      args.add("--embedder_entry_points_manifest=$dartProductEntries");
      if (!isProduct) {
        args.add("--embedder_entry_points_manifest=$dartEntries");
      }
      args.add("--vm_isolate_snapshot=$precompiledVMIsolate");
      args.add("--isolate_snapshot=$precompiledIsolate");
      args.add("--instructions_snapshot=$precompiledInstructions");
      args.add("--url_mapping=dart:vmservice_io,$vmServiceIoMain");
      args.addAll(arguments);
  
      return commandBuilder.getCompilationCommand('precompiler', tempDir, !useSdk,
  
negative.code:     // which can eventually completely replace the Map-based configuration
      // object.
      bool isDebug = configuration['mode'] == 'debug';
      bool isChecked = configuration['checked'];
      bool isHostChecked = configuration['host_checked'];
      bool useSdk = configuration['use_sdk'];
  