Fix recently introduced strong-mode errors

pkg/analysis_server/benchmark/perf/analysis_timing_tests.dart

 // Copyright (c) 2015, 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 server.performance.analysis.timing;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
@@ skipping 26 matching lines @@
   unittestConfiguration.timeout = new Duration(minutes: 20);
 
   var test;
 
   if (metricNames.isEmpty) {
     test = new AnalysisTimingTest();
   } else {
     test = new SubscriptionTimingTest();
   }
 
-  Future.wait([test.test_timing()]);
+  Future.wait(<Future>[test.test_timing()]);

[Jennifer Messerly, 2016/09/15 21:00:33]

maybe put a type on "var test" above? Then it wouldn't be needed here

[Brian Wilkerson, 2016/09/15 21:37:26]

The superclass of those two classes doesn't define `test_timing`, so we get a
different error.

 }
 
 const DEFAULT_METRIC = 'analysis';
 const METRIC_NAME_OPTION = 'metric';
 const PRIORITY_FILE_OPTION = 'priority';
 const SOURCE_OPTION = 'source';
 
 final metricNames = <String>[];
 String priorityFile;
 String source;
@@ skipping 38 matching lines @@
  * SubscriptionTimingTest measures the time taken by the analysis server to return
  * information for navigation, semantic highlighting, outline, get occurances,
  * overrides, folding and implemented. These timings are wrt to the specified priority file
  * - the file that is currently opened and has focus in the editor. Measure the time from
  * when the client subscribes for the notifications till there is a response from the server.
  * Does not wait for analysis to be complete before subscribing for notifications.
  */
 class SubscriptionTimingTest extends AbstractTimingTest {
   List<Metric> _metrics;
 
-  List<Metric> get metrics =>
-      _metrics ??= metricNames.map((name) => getMetric(name)).toList();
+  List<Metric> get metrics => _metrics ??=
+      new List<Metric>.from(metricNames.map((name) => getMetric(name)));

[Jennifer Messerly, 2016/09/15 21:00:33]

any idea what happened here? it doesn't look like something that would be
affected by any recent changes.

also just noticed, it could be: metricNames.map(getMetric)

[Brian Wilkerson, 2016/09/15 21:37:26]

Nope. I tried to reproduce the error and couldn't, so I reverted the change...
...except for this simplification.

 
   Metric getMetric(String name) {
     switch (name) {
       case 'folding':
         return new Metric(name, AnalysisService.FOLDING, onAnalysisFolding);
       case 'highlighting':
         return new Metric(
             name, AnalysisService.HIGHLIGHTS, onAnalysisHighlights);
       case 'implemented':
         return new Metric(
@@ skipping 40 matching lines @@
 
     sendAnalysisSetPriorityFiles([priorityFile]);
 
     await analysisFinished;
     print('analysis completed in ${stopwatch.elapsed}');
     metrics.forEach((Metric m) => print('${m.name} timings: ${m.timings}'));
 
     await shutdown();
   }
 }