Renaming dart:html library from 'html' to 'dart.html'

tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate

 // 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.
 
-part of html;
+part of $LIBRARYNAME;
 
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   factory $CLASSNAME() => _$(CLASSNAME)FactoryProvider.createDocumentFragment();
 
   factory $CLASSNAME.html(String html) =>
       _$(CLASSNAME)FactoryProvider.createDocumentFragment_html(html);
 
   factory $CLASSNAME.svg(String svgContent) =>
       _$(CLASSNAME)FactoryProvider.createDocumentFragment_svg(svgContent);
 
@@ skipping 59 matching lines @@
   void appendText(String text) {
     this.nodes.add(new Text(text));
   }
 
   void appendHtml(String text) {
     this.nodes.add(new DocumentFragment.html(text));
   }
 
 $!MEMBERS
 }