Removed DARTIUM codegen for IDLS (sdk/lib/dartium)

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

 // 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.
 
 // WARNING: Do not edit - generated code.
 
 part of $LIBRARYNAME;
 
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
 $!MEMBERS
-$if DART2JS
   static bool get supported =>
       JS('bool', '!!(Element.prototype.createShadowRoot||'
                  'Element.prototype.webkitCreateShadowRoot)');
-$else
-  static final bool supported = true;
-$endif
 
   static bool _shadowRootDeprecationReported = false;
   static void _shadowRootDeprecationReport() {
     if (!_shadowRootDeprecationReported) {
       window.console.warn('''
 ShadowRoot.resetStyleInheritance and ShadowRoot.applyAuthorStyles now deprecated in dart:html.
 Please remove them from your code.
 ''');
       _shadowRootDeprecationReported = true;
     }
@@ skipping 16 matching lines @@
     _shadowRootDeprecationReport();
     // Default value from when it was specified.
     return false;
   }
 
   @deprecated
   set applyAuthorStyles(bool value) {
     _shadowRootDeprecationReport();
   }
 }