test.dart: Print stack traces of all threads when a test times out

tools/testing/dart/test_runner.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 executing tests.
  *
  * This module includes:
  * - Managing parallel execution of tests, including timeout checks.
  * - Evaluating the output of each test as pass/fail/crash/timeout.
@@ skipping 1836 matching lines @@
                 watchdogTimer.cancel();
               }
             }
           }
 
           // Close stdin so that tests that try to block on input will fail.
           process.stdin.close();
           void timeoutHandler() {
             timedOut = true;
             if (process != null) {
-              if (!process.kill()) {
-                DebugLogger.error("Unable to kill ${process.pid}");
+              if (io.Platform.isLinux) {
+                // Try to print stack traces of the timed out process.
+                io.Process.run('eu-stack', ['-p ${process.pid}'])
+                .then((result) {
+                  io.stdout.write(result.stdout);
+                  io.stderr.write(result.stderr);
+                })
+                .catchError(
+                    (error) => print("Error when printing stack trace: $error"))
+                .whenComplete(() {
+                  if (!process.kill()) {
+                    DebugLogger.error("Unable to kill ${process.pid}");
+                  }
+                });
+              } else {
+                if (!process.kill()) {
+                  DebugLogger.error("Unable to kill ${process.pid}");
+                }
               }
             }
           }
 
           stdoutSubscription.asFuture().then(closeStdout);
           stderrSubscription.asFuture().then(closeStderr);
 
           process.exitCode.then((exitCode) {
             if (!stdoutDone || !stderrDone) {
               watchdogTimer = new Timer(MAX_STDIO_DELAY, () {
@@ skipping 1175 matching lines @@
     }
   }
 
   void eventAllTestsDone() {
     for (var listener in _eventListener) {
       listener.allDone();
     }
     _allDone();
   }
 }