Change how File/Directory/Link .delete works.

sdk/lib/io/link.dart

Index: sdk/lib/io/link.dart
diff --git a/sdk/lib/io/link.dart b/sdk/lib/io/link.dart
index fee4f97fc6271aef7a1e7862dc1eab7ce2af1d10..ad3e6603969ad2676d365a82e7338cb6a67e3894 100644
--- a/sdk/lib/io/link.dart
+++ b/sdk/lib/io/link.dart
@@ -164,11 +164,21 @@ class _Link extends FileSystemEntity implements Link {
   }
 
   Future<Link> delete() {
-    return new File(path).delete().then((_) => this);
+    _ensureFileService();
+    List request = new List(2);
+    request[0] = _LINK_DELETE_REQUEST;
+    request[1] = path;
+    return _fileService.call(request).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "Cannot delete file '$path'");
+      }
+      return this;
+    });
   }
 
   void deleteSync() {
-    new File(path).deleteSync();
+    var result = _File._deleteLink(path);
+    throwIfError(result, "Cannot delete file '$path'");
   }
 
   Future<String> target() {
@@ -183,6 +193,12 @@ class _Link extends FileSystemEntity implements Link {
     }
     return result;
   }
+
+  static throwIfError(Object result, String msg) {
+    if (result is OSError) {
+      throw new FileIOException(msg, result);
+    }
+  }
 }