Split up TypeInferrer class.

pkg/front_end/lib/src/fasta/source/source_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.source_library_builder;
 
 import 'package:front_end/src/fasta/scanner/token.dart' show SymbolToken, Token;
 
-import 'package:front_end/src/fasta/type_inference/type_inferrer.dart'
-    show TypeInferrer;
+import 'package:front_end/src/fasta/type_inference/type_inference_engine.dart'
+    show TypeInferenceEngine;
 
 import 'package:kernel/ast.dart' show AsyncMarker, ProcedureKind;
 
 import '../combinator.dart' show Combinator;
 
 import '../errors.dart' show inputError, internalError;
 
 import '../export.dart' show Export;
 
 import '../import.dart' show Import;
@@ skipping 457 matching lines @@
     return count;
   }
 
   List<TypeVariableBuilder> copyTypeVariables(
       List<TypeVariableBuilder> original);
 
   @override
   String get fullNameForErrors => name ?? "<library '$relativeFileUri'>";
 
   @override
-  void prepareInitializerInference(TypeInferrer typeInferrer,
+  void prepareInitializerInference(TypeInferenceEngine typeInferenceEngine,
       LibraryBuilder library, ClassBuilder currentClass) {
     forEach((String name, Builder member) {
-      member.prepareInitializerInference(typeInferrer, library, currentClass);
+      member.prepareInitializerInference(
+          typeInferenceEngine, library, currentClass);
     });
   }
 }
 
 /// Unlike [Scope], this scope is used during construction of builders to
 /// ensure types and members are added to and resolved in the correct location.
 class DeclarationBuilder<T extends TypeBuilder> {
   final DeclarationBuilder<T> parent;
 
   final Map<String, Builder> members;
@@ skipping 76 matching lines @@
   /// synthesize type variables on the factory matching the class'.
   void addFactoryDeclaration(
       ProcedureBuilder procedure, DeclarationBuilder<T> factoryDeclaration) {
     factoryDeclarations[procedure] = factoryDeclaration;
   }
 
   Scope toScope(Scope parent) {
     return new Scope(members, setters, parent, isModifiable: false);
   }
 }