Clean up duplicate type inference code for fetching parameter types.

pkg/front_end/lib/src/fasta/type_inference/type_inference_engine.dart

 // Copyright (c) 2017, 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.md file.
 
 import 'package:front_end/src/base/instrumentation.dart';
 import 'package:front_end/src/dependency_walker.dart' as dependencyWalker;
 import 'package:front_end/src/fasta/errors.dart';
 import 'package:front_end/src/fasta/kernel/kernel_shadow_ast.dart';
 import 'package:front_end/src/fasta/type_inference/type_inference_listener.dart';
 import 'package:front_end/src/fasta/type_inference/type_inferrer.dart';
@@ skipping 248 matching lines @@
     }
     for (var formal in initializingFormals) {
       formal.type = _inferInitializingFormalType(formal);
     }
   }
 
   /// Retrieve the [TypeInferrer] for the given [member], which was created by
   /// a previous call to [createTopLevelTypeInferrer].
   TypeInferrerImpl getMemberTypeInferrer(KernelMember member);
 
-  DartType getNamedParameterType(FunctionType functionType, String name) {
-    return functionType.getNamedParameter(name) ?? const DynamicType();
-  }
-
-  DartType getPositionalParameterType(FunctionType functionType, int i) {
-    if (i < functionType.positionalParameters.length) {
-      return functionType.positionalParameters[i];
-    } else {
-      return const DynamicType();
-    }
-  }
-
   /// Performs type inference on the given [accessorNode].
   void inferAccessor(AccessorNode accessorNode) {
     assert(accessorNode.state == InferenceState.NotInferredYet);
     accessorNode.state = InferenceState.Inferring;
     var member = accessorNode.member;
     if (strongMode) {
       var inferredType = tryInferAccessorByInheritance(accessorNode);
       var typeInferrer = getMemberTypeInferrer(member);
       if (inferredType == null) {
         if (member is KernelField) {
@@ skipping 310 matching lines @@
   }
 
   @override
   void evaluateScc(List<AccessorNode> scc) {
     // Mark every accessor as part of a circularity.
     for (var f in scc) {
       f._typeInferenceEngine.inferAccessorCircular(f);
     }
   }
 }