Revert "Revert "First step towards having patch files for generic libraries.""

lib/compiler/implementation/lib/web.dart

Index: lib/compiler/implementation/lib/web.dart
diff --git a/lib/dom/templates/dom/native/dart_implementation.darttemplate b/lib/compiler/implementation/lib/web.dart
similarity index 68%
copy from lib/dom/templates/dom/native/dart_implementation.darttemplate
copy to lib/compiler/implementation/lib/web.dart
index 885414fa4e9c02d40a38aa12d0718ccc0d47f85e..a75db7bf6a9d46bbfc28b7358078c7090d6aff65 100644
--- a/lib/dom/templates/dom/native/dart_implementation.darttemplate
+++ b/lib/compiler/implementation/lib/web.dart
@@ -2,8 +2,8 @@
 // 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.
 
-// WARNING: Do not edit - generated code.
+#library("web");
 
-class $CLASSNAME$EXTENDS$IMPLEMENTS {
-$!MEMBERS
+String htmlEscape(String text) {
+  throw "Unimplemented: web::htmlEscape(String).";
 }