Add bool value types to type inference.

pkg/compiler/lib/src/inferrer/inferrer_visitor.dart

Index: pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
diff --git a/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart b/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
index 08fa94517b41c3e90569a3ab0e8f72093c5fb3e4..bfd33603f67c98e4da5e13fa1ab19d58a6fd228d 100644
--- a/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
+++ b/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
@@ -58,6 +58,7 @@ abstract class TypeSystem<T> {
   T get typeType;
 
   T stringLiteralType(DartString value);
+  T boolLiteralType(LiteralBool value);
 
   T nonNullSubtype(ClassElement type);
   T nonNullSubclass(ClassElement type);
@@ -832,7 +833,7 @@ abstract class InferrerVisitor<T, E extends MinimalInferrerEngine<T>>
   }
 
   T visitLiteralBool(LiteralBool node) {
-    return types.boolType;
+    return types.boolLiteralType(node);
   }
 
   T visitLiteralDouble(LiteralDouble node) {