Add mirrors_reader_test.

sdk/lib/_internal/compiler/implementation/mirrors/source_mirrors.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 mirrors;
 
 import 'dart:mirrors';
 import 'dart:mirrors' as api show SourceLocation;
 export 'dart:mirrors';
 
@@ skipping 100 matching lines @@
  */
 abstract class LibrarySourceMirror
     implements DeclarationSourceMirror, LibraryMirror {
   /**
    * Returns a list of the imports and exports in this library;
    */
   List<LibraryDependencyMirror> get libraryDependencies;
 }
 
 /// A mirror on an import or export declaration.
-abstract class LibraryDependencyMirror {
+abstract class LibraryDependencyMirror extends Mirror {
   /// Is `true` if this dependency is an import.
   bool get isImport;
 
   /// Is `true` if this dependency is an export.
   bool get isExport;
 
   /// Returns the library mirror of the library that imports or exports the
   /// [targetLibrary].
   LibraryMirror get sourceLibrary;
 
   /// Returns the library mirror of the library that is imported or exported.
   LibraryMirror get targetLibrary;
 
   /// Returns the prefix if this is a prefixed import and `null` otherwise.
   String get prefix;
 
   /// Returns the list of show/hide combinators on the import/export
   /// declaration.
   List<CombinatorMirror> get combinators;
 
   /// Returns the source location for this import/export declaration.
   SourceLocation get location;
 }
 
 /// A mirror on a show/hide combinator declared on a library dependency.
-abstract class CombinatorMirror {
+abstract class CombinatorMirror extends Mirror {
   /// The list of identifiers on the combinator.
   List<String> get identifiers;
 
   /// Is `true` if this is a 'show' combinator.
   bool get isShow;
 
   /// Is `true` if this is a 'hide' combinator.
   bool get isHide;
 }
 
@@ skipping 82 matching lines @@
   /**
    * Returns the URI where the source originated.
    */
   Uri get sourceUri;
 
   /**
    * Returns the text of this source.
    */
   String get sourceText;
 }