Add type inference of annotations.

pkg/front_end/testcases/inference/downwards_inference_annotations_type_variable.dart

Index: pkg/front_end/testcases/inference/downwards_inference_annotations_type_variable.dart
diff --git a/pkg/front_end/testcases/inference/downwards_inference_annotations.dart b/pkg/front_end/testcases/inference/downwards_inference_annotations_type_variable.dart
similarity index 56%
copy from pkg/front_end/testcases/inference/downwards_inference_annotations.dart
copy to pkg/front_end/testcases/inference/downwards_inference_annotations_type_variable.dart
index fd31916c8fdba60cc4e6fb865ba35525d4a952b5..a5ecbcb0f61b7fde1d81473d9b4318b8b938a134 100644
--- a/pkg/front_end/testcases/inference/downwards_inference_annotations.dart
+++ b/pkg/front_end/testcases/inference/downwards_inference_annotations_type_variable.dart
@@ -7,11 +7,16 @@ library test;
 
 class Foo {
   const Foo(List<String> l);
-  const Foo.named(List<String> l);
 }
 
-@Foo(/*@typeArgs=String*/ const [])
-class Bar {}
+class C<@Foo(/*@typeArgs=String*/ const []) T> {}
 
-@Foo.named(/*@typeArgs=String*/ const [])
-class Baz {}
+typedef void F<@Foo(/*@typeArgs=String*/ const []) T>();
+
+void f<@Foo(/*@typeArgs=String*/ const []) T>() {}
+
+class D {
+  void m<@Foo(/*@typeArgs=String*/ const []) T>() {}
+}
+
+main() {}