Add BrowserManager and IframeTest for communicating with browser tests.

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 unittest.runner.browser.browser_manager;
+
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:http_parser/http_parser.dart';
+
+import '../../backend/suite.dart';
+import '../../util/multi_channel.dart';
+import '../../util/remote_exception.dart';
+import '../../utils.dart';
+import '../load_exception.dart';
+import 'iframe_test.dart';
+
+/// A class that manages the connection to a single running browser.
+///
+/// This is in charge of telling the browser which test suites to load and
+/// converting its responses into [Suite] objects.
+class BrowserManager {
+  /// The channel used to communicate with the browser.
+  ///
+  /// This is connected to a page running `static/host.dart`.
+  final MultiChannel _channel;
+
+  /// Creates a new BrowserManager that communicates with a browser over
+  /// [webSocket].
+  BrowserManager(CompatibleWebSocket webSocket)
+      : _channel = new MultiChannel(
+          webSocket.map(JSON.decode),
+          mapSink(webSocket, JSON.encode));
+
+  /// Tells the browser the load a test suite from the URL [url].
+  ///
+  /// [url] should be an HTML page with a reference to the JS-compiled test
+  /// suite. [path] is the path of the original test suite file, which is used
+  /// for reporting.
+  Future<Suite> loadSuite(String path, Uri url) {
+    var suiteChannel = _channel.virtualChannel();
+    _channel.sink.add({
+      "command": "loadSuite",
+      "url": url.toString(),
+      "channel": suiteChannel.id
+    });
+
+    // Create a nested MultiChannel because the iframe will be using a channel
+    // wrapped within the host's channel.
+    suiteChannel = new MultiChannel(suiteChannel.stream, suiteChannel.sink);
+    return suiteChannel.stream.first.then((response) {
+      if (response["type"] == "loadException") {
+        return new Future.error(new LoadException(path, response["message"]));
+      } else if (response["type"] == "error") {
+        var asyncError = RemoteException.deserialize(response["error"]);
+        return new Future.error(
+            new LoadException(path, asyncError.error),
+            asyncError.stackTrace);
+      }
+
+      return new Suite(path, response["tests"].map((test) {
+        var testChannel = suiteChannel.virtualChannel(test['channel']);
+        return new IframeTest(test['name'], testChannel);
+      }));
+    });
+  }
+}