dart2js: Use stub instances when generating ParameterStubs (adapterStubMethods).

pkg/compiler/lib/src/js_emitter/model.dart

Index: pkg/compiler/lib/src/js_emitter/model.dart
diff --git a/pkg/compiler/lib/src/js_emitter/model.dart b/pkg/compiler/lib/src/js_emitter/model.dart
index ea1e4769ed5c17d114a6a289cb64e3d8958e6dd9..d84f8ec77c3896c237569d9384597297e1289998 100644
--- a/pkg/compiler/lib/src/js_emitter/model.dart
+++ b/pkg/compiler/lib/src/js_emitter/model.dart
@@ -327,9 +327,7 @@ abstract class Method {
   Method(this.element, this.name, this.code);
 }
 
-/**
- * A method that corresponds to a method in the original Dart program.
- */
+/// A method that corresponds to a method in the original Dart program.
 class DartMethod extends Method {
   final bool needsTearOff;
   final String tearOffName;
@@ -375,17 +373,36 @@ class InstanceMethod extends DartMethod {
   }
 }
 
-/**
- * A method that is generated by the backend and has not direct correspondence
- * to a method in the original Dart program. Examples are getter and setter
- * stubs and stubs to dispatch calls to methods with optional parameters.
- */
+/// A method that is generated by the backend and has not direct correspondence
+/// to a method in the original Dart program. Examples are getter and setter
+/// stubs and stubs to dispatch calls to methods with optional parameters.
 class StubMethod extends Method {
   StubMethod(String name, js.Expression code,
              {Element element})
       : super(element, name, code);
 }
 
+
+/// A method that adapts a call to the methods calling convention.
+///
+/// For example, given a method `foo$2(x, [y: 499])` a possible adapter
+/// stub-method could be `foo$1(x) => foo$2(x, 499)`.
+///
+/// AdapterStubMethods are always attached to (static or instance) methods.
+class AdapterStubMethod extends StubMethod {
+  /// The `call` name of this adapter.
+  ///
+  /// When an instance method is torn off, it is invoked as a `call` member and
+  /// not it's original name anymore. The [callName] provides the adapter's
+  /// name when it is used this way.
+  ///
+  /// If an adapter's member can not be torn off, the [callName] is `null`.
+  String callName;
+
+  AdapterStubMethod(String name, this.callName, js.Expression code)
+      : super(name, code);
+}
+
 abstract class StaticMethod implements Method {
   Holder get holder;
 }