Add support for watch events and error notifications

pkg/analysis_server/lib/src/plugin/notification_manager.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:collection';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart' as server;
 import 'package:analysis_server/src/channel/channel.dart';
 import 'package:analysis_server/src/plugin/result_collector.dart';
 import 'package:analysis_server/src/plugin/result_converter.dart';
@@ skipping 155 matching lines @@
         plugin.AnalysisOutlineParams params =
             new plugin.AnalysisOutlineParams.fromNotification(notification);
         recordOutlines(
             pluginId,
             params.file,
             params.outline
                 .map((plugin.Outline outline) =>
                     converter.convertOutline(outline))
                 .toList());
         break;
+      case plugin.PLUGIN_NOTIFICATION_ERROR:
+        plugin.PluginErrorParams params =
+            new plugin.PluginErrorParams.fromNotification(notification);
+        // TODO(brianwilkerson) There is no indication for the client as to the
+        // fact that the error came from a plugin, let alone which plugin it
+        // came from. We should consider whether we really want to send them to
+        // the client.
+        channel.sendNotification(new server.ServerErrorParams(
+                params.isFatal, params.message, params.stackTrace)
+            .toNotification());
+        break;
     }
   }
 
   /**
    * Record error information from the plugin with the given [pluginId] for the
    * file with the given [filePath].
    */
   void recordAnalysisErrors(
       String pluginId, String filePath, List<server.AnalysisError> errorData) {
     if (errors.isCollectingFor(filePath)) {
@@ skipping 192 matching lines @@
         }
       }
       return false;
     }
 
     // TODO(brianwilkerson) Return false if error notifications are globally
     // disabled.
     return isIncluded() && !isExcluded();
   }
 }