Remove unused class DirectoryTestSuite from test script.

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
diff --git a/tools/testing/dart/test_suite.dart b/tools/testing/dart/test_suite.dart
index c9f2d7bd818766775ffa7adf995169a21f215e11..878b605abf1cd7eab89375fbd3b0bde6c5a7a43a 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -241,7 +241,7 @@ class StandardTestSuite implements TestSuite {
    *
    * If you follow that convention, then you can construct one of these like:
    *
-   *     new DirectoryTestSuite(configuration, 'path/to/mytestsuite');
+   * new StandardTestSuite.forDirectory(configuration, 'path/to/mytestsuite');
    *
    * instead of having to create a custom [StandardTestSuite] subclass. In
    * particular, if you add 'path/to/mytestsuite' to [TEST_SUITE_DIRECTORIES]
@@ -934,7 +934,7 @@ class StandardTestSuite implements TestSuite {
     if (contents.contains("@compile-error")) {
       isNegative = true;
     }
-    
+
     if (contents.contains("@runtime-error") && hasRuntime) {
       isNegative = true;
     }
@@ -1022,52 +1022,6 @@ class DartcCompilationTestSuite extends StandardTestSuite {
 }
 
 
-/**
- * A standard test suite whose file organization matches an expected structure.
- * To use this, your suite should look like:
- *
- *     dart/
- *       path/
- *         to/
- *           mytestsuite/
- *             mytestsuite.status
- *             example1_tests.dart
- *             example2_tests.dart
- *             example3_tests.dart
- *
- * The important parts:
- *
- * * The leaf directory name is the name of your test suite.
- * * The status file uses the same name.
- * * Test files are directly in that directory and end in "_tests.dart".
- *
- * If you follow that convention, then you can construct one of these like:
- *
- *     new DirectoryTestSuite(configuration, 'path/to/mytestsuite');
- *
- * instead of having to create a custom [StandardTestSuite] subclass. In
- * particular, if you add 'path/to/mytestsuite' to [TEST_SUITE_DIRECTORIES] in
- * test.dart, this will all be set up for you.
- */
-class DirectoryTestSuite extends StandardTestSuite {
-  factory DirectoryTestSuite(Map configuration, String directory) {
-    final name = directory.substring(directory.lastIndexOf('/') + 1);
-    print(name);
-
-    return new DirectoryTestSuite._internal(configuration,
-      name, directory, ['$directory/$name.status']);
-  }
-
-  DirectoryTestSuite._internal(Map configuration,
-                               String suiteName,
-                               String directoryPath,
-                               List<String> statusFilePaths)
-    : super(configuration, suiteName, directoryPath, statusFilePaths);
-
-  bool isTestFile(String filename) => filename.endsWith('_tests.dart');
-}
-
-
 class JUnitTestSuite implements TestSuite {
   Map configuration;
   String suiteName;