More strong mode changes in analysis_server

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 12 matching lines @@
 main(List<String> arguments) {
   initializeTestEnvironment();
   ArgParser parser = _createArgParser();
   var args = parser.parse(arguments);
   if (args[SOURCE_OPTION] == null) {
     print('path to source directory must be specified');
     exit(1);
   }
   source = args[SOURCE_OPTION];
   priorityFile = args[PRIORITY_FILE_OPTION];
-  metricNames.addAll(args[METRIC_NAME_OPTION]);
+  List names = args[METRIC_NAME_OPTION] as List;
+  for (var name in names) {
+    metricNames.add(name as String);
+  }
   unittestConfiguration.timeout = new Duration(minutes: 20);
 
   var test;
 
   if (metricNames.isEmpty) {
     test = new AnalysisTimingTest();
   } else {
     test = new SubscriptionTimingTest();
   }
 
@@ skipping 111 matching lines @@
 
     sendAnalysisSetPriorityFiles([priorityFile]);
 
     await analysisFinished;
     print('analysis completed in ${stopwatch.elapsed}');
     metrics.forEach((Metric m) => print('${m.name} timings: ${m.timings}'));
 
     await shutdown();
   }
 }