dart2js cps: Handle optional parameters in builder.

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

Index: pkg/compiler/lib/src/js_backend/codegen/codegen.dart
diff --git a/pkg/compiler/lib/src/js_backend/codegen/codegen.dart b/pkg/compiler/lib/src/js_backend/codegen/codegen.dart
index 51d36ecf1fca60ac5fd2685445f9b32463ce3891..b773f951f9a8642e8b5e173e54fc757832eaf8bd 100644
--- a/pkg/compiler/lib/src/js_backend/codegen/codegen.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen/codegen.dart
@@ -207,16 +207,6 @@ class CodeGenerator extends tree_ir.Visitor<dynamic, js.Expression> {
     }
   }
 
-  List<js.Expression> compileStaticArgumentList(
-      Selector selector,
-      Element target, /* TODO(karlklose): this should be the signature. */
-      List<tree_ir.Expression> arguments) {
-    return selector.makeArgumentsList(
-        target.implementation,
-        visitArguments(arguments),
-        compileConstant);
-  }
-
   @override
   js.Expression visitInvokeConstructor(tree_ir.InvokeConstructor node) {
     checkStaticTargetIsValid(node, node.target);
@@ -225,8 +215,7 @@ class CodeGenerator extends tree_ir.Visitor<dynamic, js.Expression> {
     registry.registerInstantiatedClass(node.target.enclosingClass);
     Selector selector = node.selector;
     FunctionElement target = node.target;
-    List<js.Expression> arguments =
-        compileStaticArgumentList(selector, target, node.arguments);
+    List<js.Expression> arguments = visitArguments(node.arguments);
     return buildStaticInvoke(selector, target, arguments);
   }
 
@@ -278,8 +267,7 @@ class CodeGenerator extends tree_ir.Visitor<dynamic, js.Expression> {
     }
     Selector selector = node.selector;
     FunctionElement target = node.target;
-    List<js.Expression> arguments =
-        compileStaticArgumentList(selector, target, node.arguments);
+    List<js.Expression> arguments = visitArguments(node.arguments);
     return buildStaticInvoke(selector, target, arguments);
   }