Display a pause screen in a paused browser.

lib/src/runner.dart

 // Copyright (c) 2015, 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 test.runner;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:async/async.dart';
@@ skipping 220 matching lines @@
       _reporter.pause();
 
       var bold = _configuration.color ? '\u001b[1m' : '';
       var noColor = _configuration.color ? '\u001b[0m' : '';
       print('');
       print(wordWrap(
           "${bold}The test runner is paused.${noColor} Open the dev console in "
               "${suite.platform} and set breakpoints. Once you're finished, "
               "return to this terminal and press Enter."));
 
-      // TODO(nweiz): Display something in the paused browsers indicating that
-      // they're paused.
-
-      await stdinLines.next;
+      await race([
+        suite.environment.displayPause(),
+        cancelableNext(stdinLines)
+      ]);
     } finally {
       _reporter.resume();
     }
   }
 }