Remove the checker and corresponding dead code

test/report_test.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.
 
 /// Tests for summary reporting.
 library dev_compiler.test.report_test;
 
 import 'package:test/test.dart';
 
 import 'package:dev_compiler/devc.dart';
-import 'package:dev_compiler/strong_mode.dart' show StrongModeOptions;
 
 import 'package:dev_compiler/src/analysis_context.dart';
 import 'package:dev_compiler/src/options.dart';
 import 'package:dev_compiler/src/report.dart';
 import 'package:dev_compiler/src/summary.dart';
 
 import 'testing.dart';
 
 void main() {
   test('toJson/parse', () {
     var files = {
       '/main.dart': '''
           import 'package:foo/bar.dart';
 
           test1() {
             x = "hi";
           }
       '''.replaceAll('\n          ', '\n'),
       'package:foo/bar.dart': '''
           List x;
           test2() {
             List<String> y = x;
           }
       '''.replaceAll('\n          ', '\n'),
     };
 
     var provider = createTestResourceProvider(files);
     var uriResolver = new TestUriResolver(provider);
     var srcOpts = new SourceResolverOptions(useMockSdk: true);
-    var context = createAnalysisContextWithSources(
-        new StrongModeOptions(), srcOpts,
-        fileResolvers: [uriResolver]);
+    var context =
+        createAnalysisContextWithSources(srcOpts, fileResolvers: [uriResolver]);
     var reporter = new SummaryReporter(context);
     new BatchCompiler(context, new CompilerOptions(sourceOptions: srcOpts),
         reporter: reporter).compileFromUriString('/main.dart');
 
     _verifySummary(GlobalSummary summary) {
       var mainLib = summary.loose['file:///main.dart'];
       expect(mainLib.messages.length, 2);
       var analyzerMsg = mainLib.messages[0];
       expect(analyzerMsg.kind, "AnalyzerMessage");
 
@@ skipping 10 matching lines @@
       expect(barMessage.level, "warning");
       expect(barMessage.span.text, 'x');
       expect(barMessage.span.context, '  List<String> y = x;\n');
     }
 
     var original = reporter.result;
     _verifySummary(original);
     _verifySummary(GlobalSummary.parse(original.toJsonMap()));
   });
 }