call shimStyling even if we have no template, because our extendee might have one

pkg/polymer/lib/src/declaration.dart

Index: pkg/polymer/lib/src/declaration.dart
diff --git a/pkg/polymer/lib/src/declaration.dart b/pkg/polymer/lib/src/declaration.dart
index 1b5a6625f02fa08e1e1f65120e66d0a9d9796a3d..42486c3b0bfc359610b9ac0bde9f8cbb94da0389 100644
--- a/pkg/polymer/lib/src/declaration.dart
+++ b/pkg/polymer/lib/src/declaration.dart
@@ -492,7 +492,7 @@ PolymerDeclaration _getDeclaration(String name) => _declarations[name];
 /// Using Polymer's platform/src/ShadowCSS.js passing the style tag's content.
 void _shimShadowDomStyling(DocumentFragment template, String name,
     String extendee) {
-  if (template == null || _ShadowCss == null ||!_hasShadowDomPolyfill) return;
+  if (_ShadowCss == null ||!_hasShadowDomPolyfill) return;
 
   _ShadowCss.callMethod('shimStyling', [template, name, extendee]);
 }