remove "infer from overrides" option which is now obsolete

test/testing.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 dev_compiler.src.testing;
 
 import 'dart:mirrors';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 59 matching lines @@
 ///             dynamic x = /*warning:Box*/3;
 ///           }
 ///       '''
 ///     });
 ///
 void testChecker(String name, Map<String, String> testFiles,
     {String sdkDir,
     customUrlMappings: const {},
     relaxedCasts: true,
     inferDownwards: StrongModeOptions.inferDownwardsDefault,
-    inferFromOverrides: StrongModeOptions.inferFromOverridesDefault,
     inferTransitively: StrongModeOptions.inferTransitivelyDefault,
     nonnullableTypes: StrongModeOptions.NONNULLABLE_TYPES}) {
   test(name, () {
     expect(testFiles.containsKey('/main.dart'), isTrue,
         reason: '`/main.dart` is missing in testFiles');
 
     var provider = createTestResourceProvider(testFiles);
     var uriResolver = new TestUriResolver(provider);
     // Enable task model strong mode
     AnalysisEngine.instance.useTaskModel = true;
     var context = AnalysisEngine.instance.createAnalysisContext();
     context.analysisOptions.strongMode = true;
     context.sourceFactory = createSourceFactory(
         new SourceResolverOptions(
             customUrlMappings: customUrlMappings,
             useMockSdk: sdkDir == null,
             dartSdkPath: sdkDir),
         fileResolvers: [uriResolver]);
 
     var checker = new StrongChecker(
         context,
         new StrongModeOptions(
             relaxedCasts: relaxedCasts,
             inferDownwards: inferDownwards,
-            inferFromOverrides: inferFromOverrides,
             inferTransitively: inferTransitively,
             nonnullableTypes: nonnullableTypes,
             hints: true));
 
     // Run the checker on /main.dart.
     var mainSource = uriResolver.resolveAbsolute(new Uri.file('/main.dart'));
     var initialLibrary =
         context.resolveCompilationUnit2(mainSource, mainSource);
 
     // Extract expectations from the comments in the test files, and
@@ skipping 164 matching lines @@
     expect(tokens[1], "should", reason: 'invalid error descriptor');
     expect(tokens[2], "be", reason: 'invalid error descriptor');
     if (tokens[0] == "pass") return null;
     // TODO(leafp) For now, we just use whatever the current expectation is,
     // eventually we could do more automated reporting here.
     return _parse(tokens[0]);
   }
 
   String toString() => '$level $typeName';
 }