Add additional Schedule heartbeat calls.

pkg/scheduled_test/lib/scheduled_process.dart

 // Copyright (c) 2013, 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.
 
 library scheduled_test.scheduled_process;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'scheduled_test.dart';
@@ skipping 170 matching lines @@
           "'$description'");
     });
   }
 
   /// Converts a stream of bytes to a stream of lines and returns that along
   /// with a [StreamCanceller] controlling it.
   Pair<Stream<String>, StreamCanceller> _lineStreamWithCanceller(
       Future<Stream<List<int>>> streamFuture) {
     return streamWithCanceller(futureStream(streamFuture)
         .handleError((e) => currentSchedule.signalError(e))
+        .map((chunk) {
+      // Whenever the process produces any sort of output, reset the schedule's
+      // timer.
+      currentSchedule.heartbeat();
+      return chunk;
+    })
         .transform(new StringDecoder(_encoding))
         .transform(new LineTransformer()));
   }
 
   /// Schedule an exception handler that will clean up the process and provide
   /// debug information if an error occurs.
   void _scheduleExceptionCleanup() {
     currentSchedule.onException.schedule(() {
       _stdoutCanceller();
       _stderrCanceller();
@@ skipping 129 matching lines @@
     schedule(() {
       _endExpected = true;
       return _exitCode.then((exitCode) {
         if (expectedExitCode != null) {
           expect(exitCode, equals(expectedExitCode));
         }
       });
     }, "waiting for process '$description' to exit");
   }
 }