Split up TypeInferrer class.

pkg/front_end/lib/src/fasta/source/source_library_builder.dart

Index: pkg/front_end/lib/src/fasta/source/source_library_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/source/source_library_builder.dart b/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
index 3a0985fd7039b44a01d49d6bf507669a71f3ea05..c19a28d69f3960e1c67b81d4f4c310c1a91e15dc 100644
--- a/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
@@ -6,8 +6,8 @@ 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;
 
@@ -485,10 +485,11 @@ abstract class SourceLibraryBuilder<T extends TypeBuilder, R>
   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);
     });
   }
 }