anchor.diff:    }
   
     static String compilerPath(Map configuration) {
  +    if (configuration['component'] == 'dartium') {
  +      return null;  // No separate compiler for dartium tests.
  +    }
       var name = '${buildDir(configuration)}/${compilerName(configuration)}';
       if (!(new File(name)).existsSync()) {
         throw "Executable '$name' does not exist";
  
positive.code: 
      switch (configuration['component']) {
        case 'dartium':
          enqueueDartiumTest(filename, testName, optionsFromFile,
                             expectations, isNegative);
          break;
        case 'chromium':
        case 'frogium':
          enqueueChromiumTest(filename, testName, optionsFromFile,
                              expectations, isNegative);
          break;
        default:
          // Only dartc supports fatal type errors. Enable fatal type
  
negative.code:           '$dartDir/tests/isolate/src/TestFramework.dart',
            dartLibraryFilename));
        dartWrapper.closeSync();
      } else {
        dartWrapperFilename = testPath;
        // TODO(whesse): Once test.py is retired, adjust the relative path in
        // the client/samples/dartcombat test to its css file, remove the
        // "../../" from this path, and move this out of the isWebTest guard.
        // Also remove getHtmlName, and just use test.html.
        htmlPath = '${tempDir.path}/../../${getHtmlName(filename)}';
      }
      final String scriptPath = (component == 'dartium') ?
          dartWrapperFilename : compiledDartWrapperFilename;
      // Create the HTML file for the test.
      RandomAccessFile htmlTest = new File(htmlPath).openSync(FileMode.WRITE);
      htmlTest.writeStringSync(GetHtmlContents(
          filename,
          '$dartDir/client/testing/unittest/test_controller.js',
          scriptType,
          scriptPath));
      htmlTest.closeSync();
  
      for (var vmOptions in optionsFromFile['vmOptions']) {
        List<String> compilerArgs;
        String compilerExecutable = TestUtils.compilerPath(configuration);
        switch (component) {
          case 'chromium':
            compilerArgs = ['--work', tempDir.path];
            if (configuration['mode'] ==  'release') {
  