Only fetch the Observatory URL in debug mode.

lib/src/runner/browser/browser_manager.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.browser.browser_manager;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:async/async.dart';
@@ skipping 63 matching lines @@
   /// screen.
   CancelableCompleter _pauseCompleter;
 
   /// The environment to attach to each suite.
   Future<_BrowserEnvironment> _environment;
 
   /// Starts the browser identified by [platform] and has it connect to [url].
   ///
   /// [url] should serve a page that establishes a WebSocket connection with
   /// this process. That connection, once established, should be emitted via
-  /// [future].
+  /// [future]. If [debug] is true, starts the browser in debug mode, with its
+  /// debugger interfaces on and detected.
   ///
   /// Returns the browser manager, or throws an [ApplicationException] if a
   /// connection fails to be established.
   static Future<BrowserManager> start(TestPlatform platform, Uri url,
-      Future<CompatibleWebSocket> future) {
-    var browser = _newBrowser(url, platform);
+      Future<CompatibleWebSocket> future, {bool debug: false}) {
+    var browser = _newBrowser(url, platform, debug: debug);
 
     var completer = new Completer();
 
     // TODO(nweiz): Gracefully handle the browser being killed before the
     // tests complete.
     browser.onExit.then((_) {
       throw new ApplicationException(
           "${platform.name} exited before connecting.");
     }).catchError((error, stackTrace) {
       if (completer.isCompleted) return;
@@ skipping 10 matching lines @@
     });
 
     return completer.future.timeout(new Duration(seconds: 30), onTimeout: () {
       browser.close();
       throw new ApplicationException(
           "Timed out waiting for ${platform.name} to connect.");
     });
   }
 
   /// Starts the browser identified by [browser] and has it load [url].
-  static Browser _newBrowser(Uri url, TestPlatform browser) {
+  ///
+  /// If [debug] is true, starts the browser in debug mode.
+  static Browser _newBrowser(Uri url, TestPlatform browser,
+      {bool debug: false}) {
     switch (browser) {
-      case TestPlatform.dartium: return new Dartium(url);
-      case TestPlatform.contentShell: return new ContentShell(url);
+      case TestPlatform.dartium: return new Dartium(url, debug: debug);
+      case TestPlatform.contentShell:
+        return new ContentShell(url, debug: debug);
       case TestPlatform.chrome: return new Chrome(url);
       case TestPlatform.phantomJS: return new PhantomJS(url);
       case TestPlatform.firefox: return new Firefox(url);
       case TestPlatform.safari: return new Safari(url);
       case TestPlatform.internetExplorer: return new InternetExplorer(url);
       default:
         throw new ArgumentError("$browser is not a browser.");
     }
   }
 
@@ skipping 142 matching lines @@
 /// All methods forward directly to [BrowserManager].
 class _BrowserEnvironment implements Environment {
   final BrowserManager _manager;
 
   final Uri observatoryUrl;
 
   _BrowserEnvironment(this._manager, this.observatoryUrl);
 
   CancelableFuture displayPause() => _manager._displayPause();
 }