Generate tear-off closures dynamically.

dart/sdk/lib/_internal/compiler/implementation/universe/universe.dart

Index: dart/sdk/lib/_internal/compiler/implementation/universe/universe.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/universe/universe.dart b/dart/sdk/lib/_internal/compiler/implementation/universe/universe.dart
index 8e9d50615742e89fb4871c53f5868c93c9e61418..9475947540f1841c2f17f4f445dc151c1e3b968e 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/universe/universe.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/universe/universe.dart
@@ -186,15 +186,27 @@ class Selector {
   factory Selector.fromElement(Element element, Compiler compiler) {
     String name = element.name;
     if (element.isFunction()) {
-      int arity = element.asFunctionElement().requiredParameterCount(compiler);
       if (name == '[]') {
         return new Selector.index();
       } else if (name == '[]=') {
         return new Selector.indexSet();
-      } else if (Elements.operatorNameToIdentifier(name) != name) {
-        return new Selector(SelectorKind.OPERATOR, name, null, arity);
+      }
+      FunctionSignature signature =
+          element.asFunctionElement().computeSignature(compiler);
+      int arity = signature.parameterCount;
+      List<String> namedArguments = null;
+      if (signature.optionalParametersAreNamed) {
+        namedArguments =
+            signature.orderedOptionalParameters.map((e) => e.name).toList();
+      }
+      if (Elements.operatorNameToIdentifier(name) != name) {
+        // Operators cannot have named arguments, however, that doesn't prevent
+        // a user from declaring such an operator.
+        return new Selector(
+            SelectorKind.OPERATOR, name, null, arity, namedArguments);
       } else {
-        return new Selector.call(name, element.getLibrary(), arity);
+        return new Selector.call(
+            name, element.getLibrary(), arity, namedArguments);
       }
     } else if (element.isSetter()) {
       return new Selector.setter(name, element.getLibrary());
@@ -202,6 +214,9 @@ class Selector {
       return new Selector.getter(name, element.getLibrary());
     } else if (element.isField()) {
       return new Selector.getter(name, element.getLibrary());
+    } else {
+      throw new SpannableAssertionFailure(
+          element, "Can't get selector from $element");
     }
   }
 
@@ -590,6 +605,8 @@ class Selector {
   Selector extendIfReachesAll(Compiler compiler) {
     return new TypedSelector(compiler.typesTask.dynamicType, this);
   }
+
+  Selector toCallSelector() => new Selector.callClosureFrom(this);
 }
 
 class TypedSelector extends Selector {