Begin migrating the vm service from a rest-style interface to a json-rpc style interface.

runtime/observatory/lib/service_html.dart

Index: runtime/observatory/lib/service_html.dart
diff --git a/runtime/observatory/lib/service_html.dart b/runtime/observatory/lib/service_html.dart
index da5a9759c43c68fc66202da1c02cd142852ba293..f39253c56dac56f2a75b46c71d8ab8efeedb52c4 100644
--- a/runtime/observatory/lib/service_html.dart
+++ b/runtime/observatory/lib/service_html.dart
@@ -58,46 +58,3 @@ class _HtmlWebSocket implements CommonWebSocket {
 class WebSocketVM extends CommonWebSocketVM {
   WebSocketVM(WebSocketVMTarget target) : super(target, new _HtmlWebSocket());
 }
-
-// A VM that communicates with the service via posting messages from DevTools.
-class PostMessageVM extends VM {
-  final Completer _connected = new Completer();
-  final Completer _disconnected = new Completer();
-  void disconnect() { /* nope */ }
-  Future get onConnect => _connected.future;
-  Future get onDisconnect => _disconnected.future;
-  final Map<String, Completer> _pendingRequests =
-      new Map<String, Completer>();
-  int _requestSerial = 0;
-
-  PostMessageVM() : super() {
-    window.onMessage.listen(_messageHandler);
-    _connected.complete(this);
-  }
-
-  void _messageHandler(msg) {
-    var id = msg.data['id'];
-    var name = msg.data['name'];
-    var data = msg.data['data'];
-    if (name != 'observatoryData') {
-      return;
-    }
-    var completer = _pendingRequests[id];
-    assert(completer != null);
-    _pendingRequests.remove(id);
-    completer.complete(data);
-  }
-
-  Future<String> getString(String path) {
-    var idString = '$_requestSerial';
-    Map message = {};
-    message['id'] = idString;
-    message['method'] = 'observatoryQuery';
-    message['query'] = '$path';
-    _requestSerial++;
-    var completer = new Completer();
-    _pendingRequests[idString] = completer;
-    window.parent.postMessage(JSON.encode(message), '*');
-    return completer.future;
-  }
-}