dart2js cps: Handle optional parameters in builder.

pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.ir_builder;
 
 import '../constants/expressions.dart';
 import '../constants/values.dart' show PrimitiveConstantValue;
 import '../dart_types.dart';
 import '../dart2jslib.dart';
@@ skipping 713 matching lines @@
         (k) => new ir.InvokeConstructor(type, element, selector, k, arguments));
   }
 
   /// Create a string concatenation of the [arguments].
   ir.Primitive buildStringConcatenation(List<ir.Primitive> arguments) {
     assert(isOpen);
     return _continueWithExpression(
         (k) => new ir.ConcatenateStrings(k, arguments));
   }
 
-  /// Create an invocation of [local] where the argument structure is defined
-  /// by [selector] and the argument values are defined by [arguments].
-  ir.Primitive buildLocalInvocation(LocalElement local,
-                                    Selector selector,
-                                    List<ir.Definition> arguments) {
-    return _buildInvokeCall(buildLocalGet(local), selector, arguments);
-  }
-
-  /// Create an invocation of the [functionExpression] where the argument
-  /// structure are defined by [selector] and the argument values are defined by
-  /// [arguments].
-  ir.Primitive buildFunctionExpressionInvocation(
+  /// Create an invocation of the `call` method of [functionExpression], where
+  /// the named arguments are given by [selector].
+  ir.Primitive buildCallInvocation(
       ir.Primitive functionExpression,
       Selector selector,
       List<ir.Definition> arguments) {
     return _buildInvokeCall(functionExpression, selector, arguments);
   }
 
   /// Creates an if-then-else statement with the provided [condition] where the
   /// then and else branches are created through the [buildThenPart] and
   /// [buildElsePart] functions, respectively.
   ///
@@ skipping 1260 matching lines @@
   ClosureEnvironment(this.selfReference, this.thisLocal, this.freeVariables);
 }
 
 /// Information about which variables are captured by a nested function.
 ///
 /// This is used by the [DartIrBuilder] instead of [ClosureScope] and
 /// [ClosureEnvironment].
 abstract class DartCapturedVariableInfo {
   Iterable<Local> get capturedVariables;
 }