Change dart:io to use Future for one-shot operations.

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 41 matching lines @@
   void forEachTest(Function onTest, Map testCache, String globalTempDir(),
                    [Function onDone]);
 }
 
 
 class CCTestListerIsolate extends Isolate {
   CCTestListerIsolate() : super.heavy();
 
   void main() {
     port.receive((String runnerPath, SendPort replyTo) {
-      var p = new Process.start(runnerPath, ["--list"]);
+      var p = Process.start(runnerPath, ["--list"]);
       StringInputStream stdoutStream = new StringInputStream(p.stdout);
       List<String> tests = new List<String>();
       stdoutStream.onLine = () {
         String line = stdoutStream.readLine();
         while (line != null) {
           tests.add(line);
           line = stdoutStream.readLine();
         }
       };
       p.onError = (error) {
@@ skipping 252 matching lines @@
       ReadTestExpectationsInto(testExpectations,
                                '$dartDir/$statusFilePath',
                                configuration,
                                statusFileRead);
     }
   }
 
   void processDirectory() {
     directoryPath = '$dartDir/$directoryPath';
     Directory dir = new Directory(directoryPath);
-    dir.onError = (s) {
-      throw s;
-    };
-    dir.exists((bool exists) {
+    dir.exists().then((exists) {
       if (!exists) {
         print('Directory containing tests not found: $directoryPath');
         directoryListingDone(false);
       } else {
-        dir.onFile = processFile;
-        dir.onDone = directoryListingDone;
-        dir.list(recursive: listRecursively());
+        var lister = dir.list(recursive: listRecursively());
+        lister.onFile = processFile;
+        lister.onDone = directoryListingDone;
       }
     });
   }
 
   void enqueueTestCaseFromTestInformation(TestInformation info) {
     var filename = info.filename;
     var optionsFromFile = info.optionsFromFile;
     var isNegative = info.isNegative;
 
     // Look up expectations in status files using a modified file path.
@@ skipping 691 matching lines @@
     directoryPath = '$dartDir/$directoryPath';
     // Enqueueing the directory listers is an activity.
     activityStarted();
     for (String testDir in _testDirs) {
       Directory dir = new Directory("$directoryPath/$testDir");
       if (dir.existsSync()) {
         activityStarted();
         dir.onError = (s) {
           throw s;
         };
-        dir.onFile = processFile;
-        dir.onDone = (ignore) => activityCompleted();
-        dir.list(recursive: listRecursively());
+        var lister = dir.list(recursive: listRecursively());
+        lister.onFile = processFile;
+        lister.onDone = (ignore) => activityCompleted();
       }
     }
     // Completed the enqueueing of listers.
     activityCompleted();
   }
 }
 
 
 class JUnitTestSuite implements TestSuite {
   Map configuration;
@@ skipping 44 matching lines @@
     processDirectory();
   }
 
   void processDirectory() {
     directoryPath = '$dartDir/$directoryPath';
     Directory dir = new Directory(directoryPath);
 
     dir.onError = (s) {
       throw s;
     };
-    dir.onFile = processFile;
-    dir.onDone = createTest;
-    dir.list(recursive: true);
+    var lister = dir.list(recursive: true);
+    lister.onFile = processFile;
+    lister.onDone = createTest;
   }
 
   void processFile(String filename) {
     if (!isTestFile(filename)) return;
 
     int index = filename.indexOf('compiler/javatests/com/google/dart');
     if (index != -1) {
       String testRelativePath =
           filename.substring(index + 'compiler/javatests/'.length,
                              filename.length - '.java'.length);
@@ skipping 265 matching lines @@
  * $noCrash tests are expected to be flaky but not crash
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout
 """;
     print(report);
    }
 }