All strong mode cleaning of dart2js.

pkg/compiler/lib/src/js_backend/no_such_method_registry.dart

Index: pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
diff --git a/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart b/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
index bfd4df4dd30bf82afc72503e1aad3f2f206649c0..a8cb23f9eccc9ba2bacfae0f2cb91abb9bd2d3da 100644
--- a/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
+++ b/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
@@ -195,14 +195,14 @@ abstract class NoSuchMethodResolver {
   ///
   ///     noSuchMethod(i) => super.noSuchMethod(i);
   ///
-  bool hasForwardingSyntax(FunctionEntity method);
+  bool hasForwardingSyntax(covariant FunctionEntity method);
 
   /// Computes whether [method] is of the form
   ///
   ///     noSuchMethod(i) => throw new Error();
   ///
-  bool hasThrowingSyntax(FunctionEntity method);
+  bool hasThrowingSyntax(covariant FunctionEntity method);
 
   /// Returns the `noSuchMethod` that [method] overrides.
-  FunctionEntity getSuperNoSuchMethod(FunctionEntity method);
+  FunctionEntity getSuperNoSuchMethod(covariant FunctionEntity method);
 }