Mirrors overhaul.

R=johnniwinther@google.com

Review URL: https://codereview.chromium.org//23455028

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/path@29551 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/lib/path.dart b/lib/path.dart
index dafb0c2..da4c935 100644
--- a/lib/path.dart
+++ b/lib/path.dart
@@ -90,7 +90,8 @@
 /// return the current URL.
 String get current {
   if (_io != null) {
-    return _io.classes[#Directory].getField(#current).reflectee.path;
+    return (_io.declarations[#Directory] as ClassMirror)
+        .getField(#current).reflectee.path;
   } else if (_html != null) {
     return _html.getField(#window).reflectee.location.href;
   } else {
@@ -867,7 +868,7 @@
   static Style _getPlatformStyle() {
     if (_io == null) return Style.url;
 
-    if (_io.classes[#Platform].getField(#operatingSystem)
+    if ((_io.declarations[#Platform] as ClassMirror).getField(#operatingSystem)
         .reflectee == 'windows') {
       return Style.windows;
     }