remove "infer from overrides" option which is now obsolete

lib/src/checker/checker.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.checker.checker;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/scanner.dart' show Token, TokenType;
 
 import '../../strong_mode.dart' show StrongModeOptions;
 import '../info.dart';
 import '../utils.dart' show getMemberType;
 import 'rules.dart';
 
 /// Checks for overriding declarations of fields and methods. This is used to
 /// check overrides between classes and superclasses, interfaces, and mixin
 /// applications.
 class _OverrideChecker {
   bool _failure = false;
   final TypeRules _rules;
   final AnalysisErrorListener _reporter;
-  final bool _inferFromOverrides;
-  _OverrideChecker(this._rules, this._reporter, StrongModeOptions options)
-      : _inferFromOverrides = options.inferFromOverrides;
+
+  _OverrideChecker(this._rules, this._reporter);
 
   void check(ClassDeclaration node) {
     if (node.element.type.isObject) return;
     _checkSuperOverrides(node);
     _checkMixinApplicationOverrides(node);
     _checkAllInterfaceOverrides(node);
   }
 
   /// Check overrides from mixin applications themselves. For example, in:
   ///
@@ skipping 292 matching lines @@
   final AnalysisErrorListener reporter;
   final _OverrideChecker _overrideChecker;
   bool _failure = false;
   bool get failure => _failure || _overrideChecker._failure;
 
   void reset() {
     _failure = false;
     _overrideChecker._failure = false;
   }
 
-  CodeChecker(TypeRules rules, AnalysisErrorListener reporter,
-      StrongModeOptions options)
+  CodeChecker(TypeRules rules, AnalysisErrorListener reporter)
       : rules = rules,
         reporter = reporter,
-        _overrideChecker = new _OverrideChecker(rules, reporter, options);
+        _overrideChecker = new _OverrideChecker(rules, reporter);
 
   @override
   void visitCompilationUnit(CompilationUnit unit) {
     void report(Expression expr) {
       reporter.onError(new MissingTypeError(expr).toAnalysisError());
     }
     var callback = rules.reportMissingType;
     rules.reportMissingType = report;
     unit.visitChildren(this);
     rules.reportMissingType = callback;
@@ skipping 607 matching lines @@
     if (info is CoercionInfo) {
       // TODO(jmesserly): if we're run again on the same AST, we'll produce the
       // same annotations. This should be harmless. This might go away once
       // CodeChecker is integrated better with analyzer, as it will know that
       // checking has already been performed.
       // assert(CoercionInfo.get(info.node) == null);
       CoercionInfo.set(info.node, info);
     }
   }
 }