Remove files that have already been ported or do not need to be ported.

client/html/src/_FactoryProviders.dart

-// Copyright (c) 2011, 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.
-
-
-// These factory methods could all live in one factory provider class but dartc
-// has a bug (5399939) preventing that.
-
-class FileReaderFactoryProvider {
-
-  factory FileReader() {
-    return new dom.FileReader();
-  }
-}
-
-class CSSMatrixFactoryProvider {
-
-  factory CSSMatrix([String spec = '']) {
-    return new CSSMatrixWrappingImplementation._wrap(
-        new dom.WebKitCSSMatrix(spec));
-  }
-}
-
-class PointFactoryProvider {
-
-  factory Point(num x, num y) {
-    return new PointWrappingImplementation._wrap(new dom.WebKitPoint(x, y));
-  }
-}