cache completion performance by default

pkg/analysis_server/lib/src/domain_completion.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 domain.completion;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
@@ skipping 40 matching lines @@
   /**
    * A list of code completion peformance measurements for the latest
    * completion operation up to [performanceListMaxLength] measurements.
    */
   final List<CompletionPerformance> performanceList =
       new List<CompletionPerformance>();
 
   /**
    * The maximum number of performance measurements to keep.
    */
-  static const int performanceListMaxLength = 0;
+  static const int performanceListMaxLength = 50;
 
   /**
    * Performance for the last priority change event.
    */
   CompletionPerformance priorityChangedPerformance;
 
   /**
    * Initialize a new request handler for the given [server].
    */
   CompletionDomainHandler(this.server) {
@@ skipping 125 matching lines @@
         completionId).toResponse(request.id);
   }
 
   /**
    * If tracking code completion performance over time, then
    * record addition information about the request in the performance record.
    */
   void recordRequest(CompletionPerformance performance, AnalysisContext context,
       Source source, int offset) {
     performance.source = source;
-    performance.offset = offset;
     if (priorityChangedPerformance != null &&
         priorityChangedPerformance.source != source) {
       priorityChangedPerformance = null;
     }
     if (performanceListMaxLength == 0 || context == null || source == null) {
       return;
     }
     TimestampedData<String> data = context.getContents(source);
     if (data == null) {
       return;
     }
-    performance.contents = data.data;
+    performance.setContentsAndOffset(data.data, offset);
     while (performanceList.length >= performanceListMaxLength) {
       performanceList.removeAt(0);
     }
     performanceList.add(performance);
   }
 
   /**
    * Send completion notification results.
    */
   void sendCompletionNotification(String completionId, int replacementOffset,
@@ skipping 37 matching lines @@
     if (_sourcesChangedSubscription != null) {
       _sourcesChangedSubscription.cancel();
       _sourcesChangedSubscription = null;
     }
     if (_manager != null) {
       _manager.dispose();
       _manager = null;
     }
   }
 }