Don't schedule indexing operations if index is null.

pkg/analysis_server/lib/src/operation/operation_analysis.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.analysis;
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/computer/computer_highlights.dart';
 import 'package:analysis_server/src/computer/computer_navigation.dart';
 import 'package:analysis_server/src/computer/computer_occurrences.dart';
 import 'package:analysis_server/src/computer/computer_outline.dart';
 import 'package:analysis_server/src/computer/computer_overrides.dart';
 import 'package:analysis_server/src/operation/operation.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/html.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * Schedules indexing of the given [file] using the resolved [dartUnit].
  */
 void scheduleIndexOperation(AnalysisServer server, String file,
     AnalysisContext context, CompilationUnit dartUnit) {
-  server.addOperation(new _DartIndexOperation(context, file, dartUnit));
+  if (server.index != null) {
+    server.addOperation(new _DartIndexOperation(context, file, dartUnit));
+  }
 }
 
 /**
  * Schedules sending notifications for the given [file] using the resolved
  * [resolvedDartUnit].
  */
 void scheduleNotificationOperations(AnalysisServer server, String file,
     LineInfo lineInfo, AnalysisContext context, CompilationUnit parsedDartUnit,
     CompilationUnit resolvedDartUnit, List<AnalysisError> errors) {
   // Dart
@@ skipping 191 matching lines @@
   }
 
   void _setCacheSize(int cacheSize) {
     AnalysisOptionsImpl options =
         new AnalysisOptionsImpl.con1(context.analysisOptions);
     options.cacheSize = cacheSize;
     context.analysisOptions = options;
   }
 
   void _updateIndex(AnalysisServer server, List<ChangeNotice> notices) {
-    Index index = server.index;
-    if (index == null) {
+    if (server.index == null) {
       return;
     }
     for (ChangeNotice notice in notices) {
       String file = notice.source.fullName;
       // Dart
       try {
         CompilationUnit dartUnit = notice.resolvedDartUnit;
         if (dartUnit != null) {
           server.addOperation(new _DartIndexOperation(context, file, dartUnit));
         }
@@ skipping 142 matching lines @@
 abstract class _SingleFileOperation extends SourceSensitiveOperation {
   final String file;
 
   _SingleFileOperation(AnalysisContext context, this.file) : super(context);
 
   @override
   bool shouldBeDiscardedOnSourceChange(Source source) {
     return source.fullName == file;
   }
 }