Don't send notifications for disposed contexts.

pkg/analysis_server/lib/src/operation/operation_queue.dart

Index: pkg/analysis_server/lib/src/operation/operation_queue.dart
diff --git a/pkg/analysis_server/lib/src/operation/operation_queue.dart b/pkg/analysis_server/lib/src/operation/operation_queue.dart
index 7ea825759599e6e047531dc6ef25c9c6a66f3a3c..8163174859ae0e10072529854369dbd1ebda4278 100644
--- a/pkg/analysis_server/lib/src/operation/operation_queue.dart
+++ b/pkg/analysis_server/lib/src/operation/operation_queue.dart
@@ -8,6 +8,7 @@ import 'dart:collection';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/operation/operation.dart';
+import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
@@ -51,6 +52,17 @@ class ServerOperationQueue {
   }
 
   /**
+   * The given [context] has been removed, so all pending operations that refer
+   * to it should be removed from the queue.
+   */
+  void contextRemoved(AnalysisContext context) {
+    for (Queue<ServerOperation> queue in _queues) {
+      queue.removeWhere(
+          (ServerOperation operation) => operation.context == context);

[scheglov, 2015/03/06 00:37:23]

IMHO if there is a line break, the function is too complex to use  the
expression body style.

[Paul Berry, 2015/03/06 01:11:09]

Hmm, I'm not sure if I agree with the general principle, but it was pretty easy
to squeeze down to one line by removing the type annotation.  Done :)

+    }
+  }
+
+  /**
    * Return the next operation to perform, or `null` if the queue is empty.
    * This method does not change the queue.
    */