Make LibraryMirror.members an internal native and lazy.

runtime/lib/mirrors_impl.dart

Index: runtime/lib/mirrors_impl.dart
===================================================================
--- runtime/lib/mirrors_impl.dart	(revision 25418)
+++ runtime/lib/mirrors_impl.dart	(working copy)
@@ -793,10 +793,8 @@
     implements LibraryMirror {
   _LocalLibraryMirrorImpl(reflectee,
                           String simpleName,
-                          String url,
-                          Map<String, Mirror> members)
+                          String url)
       : this.simpleName = _s(simpleName),
-        this.members = _convertStringToSymbolMap(members),
         this.uri = Uri.parse(url),
         super(reflectee);
 
@@ -820,8 +818,16 @@
   }
 
   final Uri uri;
-  final Map<Symbol, Mirror> members;
 
+  Map<Symbol, Mirror> _members;
+
+  Map<Symbol, Mirror> get members {
+    if (_members == null) {
+      _members = _makeMemberMap(_computeMembers(_reflectee));
+    }
+    return _members;
+  }
+
   Map<Symbol, ClassMirror> _classes = null;
   Map<Symbol, MethodMirror> _functions = null;
   Map<Symbol, MethodMirror> _getters = null;
@@ -884,6 +890,9 @@
 
   _invokeSetter(reflectee, setterName, value)
       native 'LibraryMirror_invokeSetter';
+
+  _computeMembers(reflectee)
+      native "LibraryMirror_members";
 }
 
 class _LocalMethodMirrorImpl extends _LocalDeclarationMirrorImpl