Implement type inference for conventional for-loops.

pkg/front_end/lib/src/fasta/type_inference/type_inference_listener.dart

Index: pkg/front_end/lib/src/fasta/type_inference/type_inference_listener.dart
diff --git a/pkg/front_end/lib/src/fasta/type_inference/type_inference_listener.dart b/pkg/front_end/lib/src/fasta/type_inference/type_inference_listener.dart
index ac704c49ac9075d2ca31664c090224d8049583de..197e16f663861f2dae6a7fea478efedf4bc99d43 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/type_inference_listener.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/type_inference_listener.dart
@@ -149,6 +149,12 @@ class TypeInferenceListener
   void forInStatementExit(ForInStatement statement) =>
       debugStatementExit('forInStatement', statement);
 
+  void forStatementEnter(ForStatement statement) =>
+      debugStatementEnter('forStatement', statement);
+
+  void forStatementExit(ForStatement statement) =>
+      debugStatementExit('forStatement', statement);
+
   void functionDeclarationEnter(FunctionDeclaration statement) =>
       debugStatementEnter('functionDeclaration', statement);