Reverts the following two commits:

pkg/compiler/lib/src/elements/elements.dart

 // Copyright (c) 2012, 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 elements;
 
 import '../common.dart';
 import '../common/resolution.dart' show Resolution;
 import '../compiler.dart' show Compiler;
 import '../constants/constructors.dart';
@@ skipping 1095 matching lines @@
     implements FunctionTypedElement, TypedElement, AstElement {
   /// Use [functionDeclaration] instead.
   @deprecated
   get enclosingElement;
 
   /// The function, typedef or inline function-typed parameter on which
   /// this parameter is declared.
   FunctionTypedElement get functionDeclaration;
 
   VariableDefinitions get node;
-
-  /// Whether the parameter is unnamed in a function type.
-  bool get isUnnamed;
 }
 
 /// A formal parameter of a function or constructor.
 ///
 /// Normal parameter that introduce a local variable are modeled by
 /// [LocalParameterElement] whereas initializing formals, that is parameter of
 /// the form `this.x`, are modeled by [InitializingFormalElement].
 abstract class ParameterElement extends Element
     implements VariableElement, FormalElement, LocalElement {
   /// Use [functionDeclaration] instead.
@@ skipping 792 matching lines @@
   /// by a field.
   bool get isDeclaredByField;
 
   /// Returns `true` if this member is abstract.
   bool get isAbstract;
 
   /// If abstract, [implementation] points to the overridden concrete member,
   /// if any. Otherwise [implementation] points to the member itself.
   Member get implementation;
 }