Fix CCTestSuite in test.dart.

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 0b9c8fd5f3fb02361f494ea4c6f731d75b38ea8e..99c0e959383da72adeed0e2d1f7efd3ba912a705 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -65,28 +65,32 @@ bool Contains(element, collection) => collection.indexOf(element) >= 0;
 
 void ccTestLister() {
   port.receive((String runnerPath, SendPort replyTo) {
-    void processErrorHandler(error) {
-    }
     Future processFuture = Process.start(runnerPath, ["--list"]);
     processFuture.then((p) {
       StringInputStream stdoutStream = new StringInputStream(p.stdout);
-      List<String> tests = new List<String>();
+      var streamDone = false;
+      var processExited = false;
+      checkDone() {
+        if (streamDone && processExited) {
+          replyTo.send("");
+        }
+      }
       stdoutStream.onLine = () {
         String line = stdoutStream.readLine();
-        while (line != null) {
-          tests.add(line);
-          line = stdoutStream.readLine();
-        }
+        replyTo.send(line);
+      };
+      stdoutStream.onClosed = () {
+        streamDone = true;
+        checkDone();
       };
       p.onExit = (code) {
         if (code < 0) {
           print("Failed to list tests: $runnerPath --list");
           replyTo.send("");
+        } else {
+          processExited = true;
+          checkDone();
         }
-        for (String test in tests) {
-          replyTo.send(test);
-        }
-        replyTo.send("");
       };
       port.close();
     });