Split up TypeInferrer class.

pkg/front_end/lib/src/fasta/kernel/kernel_library_builder.dart

 // Copyright (c) 2016, 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 fasta.kernel_library_builder;
 
 import 'package:front_end/src/fasta/scanner/token.dart' show Token;
 
 import 'package:kernel/ast.dart';
 
@@ skipping 147 matching lines @@
             modifiers, mixinApplication, interfaces, this, charOffset);
     // Nested declaration began in `OutlineBuilder.beginNamedMixinApplication`.
     endNestedDeclaration().resolveTypes(typeVariables, this);
     addBuilder(name, builder, charOffset);
   }
 
   void addField(List<MetadataBuilder> metadata, int modifiers,
       KernelTypeBuilder type, String name, int charOffset, Token initializer) {
     addBuilder(
         name,
-        new KernelFieldBuilder(loader.astFactory, loader.topLevelTypeInferrer,
+        new KernelFieldBuilder(loader.astFactory, loader.typeInferenceEngine,
             metadata, type, name, modifiers, this, charOffset, initializer),
         charOffset);
   }
 
   String computeAndValidateConstructorName(String name, int charOffset) {
     String className = currentDeclaration.name;
     bool startsWithClassName = name.startsWith(className);
     if (startsWithClassName && name.length == className.length) {
       // Unnamed constructor or factory.
       return "";
@@ skipping 362 matching lines @@
   }
 
   @override
   void includePart(covariant KernelLibraryBuilder part) {
     super.includePart(part);
     nativeMethods.addAll(part.nativeMethods);
     boundlessTypeVariables.addAll(part.boundlessTypeVariables);
     assert(mixinApplicationClasses.isEmpty);
   }
 }