Extract analysis/notifications into a separate operation/file.

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

 // Copyright (c) 2014, 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.
 
 library operation.queue;
 
 import 'dart:collection';
 
 import 'package:analysis_server/src/analysis_server.dart';
+import 'package:analysis_server/src/operation/operation_analysis.dart';
 import 'package:analysis_server/src/operation/operation.dart';
 
 
 /**
  * A queue of operations in an [AnalysisServer].
  */
 class ServerOperationQueue {
   final List<ServerOperationPriority> _analysisPriorities = [
       ServerOperationPriority.ANALYSIS_CONTINUE,
       ServerOperationPriority.ANALYSIS];
@@ skipping 53 matching lines @@
     for (Queue<ServerOperation> queue in _queues) {
       if (!queue.isEmpty) {
         return queue.removeFirst();
       }
     }
     // empty
     return null;
   }
 }