Initial GUI for VM service

runtime/bin/vmservice/client/packages/observatory/src/observatory/request_manager.dart

Index: runtime/bin/vmservice/client/packages/observatory/src/observatory/request_manager.dart
diff --git a/runtime/bin/vmservice/client/packages/observatory/src/observatory/request_manager.dart b/runtime/bin/vmservice/client/packages/observatory/src/observatory/request_manager.dart
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+// 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.
+
+part of observatory;
+
+/// A request response interceptor is called for each response.
+typedef void RequestResponseInterceptor();
+
+abstract class RequestManager extends Object with ChangeNotifierMixin {
+  ObservatoryApplication _application;
+  ObservatoryApplication get application => _application;
+  RequestResponseInterceptor interceptor;
+
+  /// The default request prefix is 127.0.0.1 on port 8181.
+  @observable String get prefix => __$prefix; String __$prefix = 'http://127.0.0.1:8181'; set prefix(String value) { __$prefix = notifyPropertyChange(#prefix, __$prefix, value); }
+  /// List of responses.
+  @observable List<Map> get responses => __$responses; List<Map> __$responses = toObservable([]); set responses(List<Map> value) { __$responses = notifyPropertyChange(#responses, __$responses, value); }
+
+  /// Parse
+  void parseResponses(String responseString) {
+    var r = JSON.decode(responseString);
+    if (r is Map) {
+      setResponses([r]);
+    } else {
+      setResponses(r);
+    }
+  }
+
+  void setResponses(List<Map> r) {
+    responses = toObservable(r);
+    if (interceptor != null) {
+      interceptor();
+    }
+  }
+
+  void setResponseError(String error) {
+    setResponses([{
+      'type': 'RequestError',
+      'error': error
+    }]);
+  }
+
+  /// Request [requestString] from the VM service. Updates [responses].
+  /// Will trigger [interceptor] if one is set.
+  Future<Map> get(String requestString) {
+    request(requestString).then((responseString) {
+      parseResponses(responseString);
+    }).catchError((e) {
+      setResponseError(e.toString());
+    });
+  }
+
+  /// Abstract method. Given the [requestString], return a String in the
+  /// future which contains the reply from the VM service.
+  Future<String> request(String requestString);
+}
+
+
+class HttpRequestManager extends RequestManager {
+  Future<String> request(String requestString) {
+    return HttpRequest.getString(prefix + requestString);
+  }
+}