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

runtime/bin/vmservice/server.dart

Index: runtime/bin/vmservice/server.dart
diff --git a/runtime/bin/vmservice/server.dart b/runtime/bin/vmservice/server.dart
index 17512580d5e0738c717910b532109fa75c9b51c8..46cff7b8ba1cc8ba302d62f5e556accb2debb574 100644
--- a/runtime/bin/vmservice/server.dart
+++ b/runtime/bin/vmservice/server.dart
@@ -30,20 +30,29 @@ class WebSocketClient extends Client {
         socket.close(NOT_MAP_ERROR_CODE, 'Message must be a JSON map.');
         return;
       }
-      var seq = map['seq'];
-      onMessage(seq, new Message.fromUri(Uri.parse(map['request'])));
+      var serial = map['id'];
+
+      // If the map contains 'params' then this is a JsonRPC message.
+      // We are currently in the process of switching the vmservice over to
+      // JsonRPC.
+      if (map['params'] != null) {
+        onMessage(serial, new Message.fromJsonRpc(map['method'],
+                                                  map['params']));
+      } else {
+        onMessage(serial, new Message.fromUri(Uri.parse(map['method'])));
+      }
     } else {
       socket.close(BINARY_MESSAGE_ERROR_CODE, 'Message must be a string.');
     }
   }
 
-  void post(var seq, dynamic response) {
+  void post(var serial, dynamic response) {
     try {
       Map map = {
-        'seq': seq,
+        'id': serial,
         'response': response
       };
-      if (seq == null && response is! String) {
+      if (serial == null && response is! String) {
         socket.add(response);
       } else {
         socket.add(JSON.encode(map));
@@ -69,7 +78,7 @@ class HttpRequestClient extends Client {
 
   HttpRequestClient(this.request, service) : super(service);
 
-  void post(var seq, String response) {
+  void post(var serial, String response) {
     request.response..headers.contentType = jsonContentType
                     ..write(response)
                     ..close();