cache suggestions on change in priority sources

pkg/analysis_server/lib/src/services/completion/dart_completion_manager.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 services.completion.dart;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/completion/arglist_computer.dart';
@@ skipping 57 matching lines @@
    */
   factory DartCompletionManager.create(AnalysisContext context,
       SearchEngine searchEngine, Source source) {
     return new DartCompletionManager(
         context,
         searchEngine,
         source,
         new DartCompletionCache(context, source));
   }
 
+  @override
+  void computeCache() {
+    waitForAnalysis().then((CompilationUnit unit) {
+      if (unit != null && !cache.isImportInfoCached(unit)) {
+        cache.computeImportInfo(unit, searchEngine);
+      }
+    });
+  }
+
   /**
    * Compute suggestions based upon cached information only
    * then send an initial response to the client.
    * Return a list of computers for which [computeFull] should be called
    */
   List<DartCompletionComputer> computeFast(DartCompletionRequest request) {
     return request.performance.logElapseTime('computeFast', () {
       CompilationUnit unit = context.parseCompilationUnit(source);
       request.unit = unit;
       request.node = new NodeLocator.con1(request.offset).searchWithin(unit);
@@ skipping 170 matching lines @@
   _ReplacementOffsetBuilder(this.request) {
     request.replacementOffset = request.offset;
     request.replacementLength = 0;
   }
 
   visitSimpleIdentifier(SimpleIdentifier node) {
     request.replacementOffset = node.offset;
     request.replacementLength = node.length;
   }
 }