Reapply dom_deprecated removal with non-editor breaking change.

samples/matrix/matrix_server.dart

Index: samples/matrix/matrix_server.dart
===================================================================
--- samples/matrix/matrix_server.dart	(revision 11701)
+++ samples/matrix/matrix_server.dart	(working copy)
@@ -1,13 +0,0 @@
-// 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 definition file for the matrix library for non-browser
- * applications.  (This gets Float32Array from float32.dart, rather
- * than #import'ing dart:dom_deprecated.)
- */
-#library("matrix");
-#import("dart:math", prefix: "Math");
-#source("matrix4.dart");
-#source("float32.dart");