Add top level type inference logic for integer literals.

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

Index: pkg/front_end/lib/src/fasta/source/source_class_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
index ab99c7eb462e7b36fe58335ab5d8353e1f748dc6..475af6708dea3d25021fa633861d87fc660d4633 100644
--- a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
@@ -4,6 +4,12 @@
 
 library fasta.source_class_builder;
 
+import 'package:front_end/src/fasta/builder/class_builder.dart'
+    show ClassBuilder;
+
+import 'package:front_end/src/fasta/type_inference/type_inferrer.dart'
+    show TypeInferrer;
+
 import 'package:kernel/ast.dart'
     show Class, Constructor, Supertype, TreeNode, setParents;
 
@@ -147,4 +153,12 @@ class SourceClassBuilder extends KernelClassBuilder {
     memberBuilder.next = constructorScopeBuilder[name];
     constructorScopeBuilder.addMember(name, memberBuilder);
   }
+
+  @override
+  void prepareInitializerInference(TypeInferrer typeInferrer,
+      LibraryBuilder library, ClassBuilder currentClass) {
+    scope.forEach((name, builder) {
+      builder.prepareInitializerInference(typeInferrer, library, this);
+    });
+  }
 }