Don't remove indexing operations on potential source changes.

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));
+}
+
+
+/**
  * 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) {
   // Only send notifications if the current context is the preferred
   // context for the file.  This avoids redundant notification messages
   // being sent to the client (see dartbug.com/22210).
   // TODO(paulberry): note that there is a small risk that this will cause
@@ skipping 388 matching lines @@
 abstract class _SingleFileOperation extends SourceSensitiveOperation {
   final String file;
 
   _SingleFileOperation(this.file);
 
   @override
   bool shouldBeDiscardedOnSourceChange(Source source) {
     return source.fullName == file;
   }
 }