Send 'server.error' notification in case of an exception during performing an operation.

pkg/analysis_server/lib/src/protocol.dart

Index: pkg/analysis_server/lib/src/protocol.dart
diff --git a/pkg/analysis_server/lib/src/protocol.dart b/pkg/analysis_server/lib/src/protocol.dart
index f2750014fe99b3fe32119452cc59470f2f5bce74..03d99cf429499b5c44a2e5718a2a308f56cd12d2 100644
--- a/pkg/analysis_server/lib/src/protocol.dart
+++ b/pkg/analysis_server/lib/src/protocol.dart
@@ -900,7 +900,7 @@ class Notification {
    * sent to the client to represent this response.
    */
   Map<String, Object> toJson() {
-    Map<String, Object> jsonObject = new HashMap<String, Object>();
+    Map<String, Object> jsonObject = {};
     jsonObject[EVENT] = event;
     if (!params.isEmpty) {
       jsonObject[PARAMS] = params;