Fix copy_dart to correctly put library comments BEFORE the library directive.

tools/dom/templates/html/dart2js/chrome_dart2js.darttemplate

 
 // Copyright (c) 2013, 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.
 
 // DO NOT EDIT - unless you are editing documentation as per:
 // https://code.google.com/p/dart/wiki/ContributingHTMLDocumentation
 // Auto-generated dart:chrome library.
 
 /// Native wrappers for the Chrome Packaged App APIs.
 ///
 /// These functions allow direct access to the Packaged App APIs, allowing
 /// Chrome Packaged Apps to be written using Dart.
 ///
-/// For more information on these APIs, see the Chrome.* APIs Documentation:
-///   http://developer.chrome.com/extensions/api_index.html
+/// For more information on these APIs, see the
+/// [Chrome APIs Documentation](http://developer.chrome.com/extensions/api_index.html)
 library chrome;
 
 import 'dart:_foreign_helper' show JS;
 /* TODO(sashab): Add "show convertDartClosureToJS" once 'show' works. */
 import 'dart:_js_helper';
 import 'dart:html_common';
 import 'dart:html';
 
 part "$AUXILIARY_DIR/chrome/utils.dart";
 part "$AUXILIARY_DIR/chrome/chrome.dart";
 
 // Generated files below this line.
 part "$AUXILIARY_DIR/chrome/app_window.dart";
 part "$AUXILIARY_DIR/chrome/app_runtime.dart";