pkg/csslib: fixed analysis error, more cleanup

pkg/csslib/lib/src/tree_printer.dart

Index: pkg/csslib/lib/src/tree_printer.dart
diff --git a/pkg/csslib/lib/src/tree_printer.dart b/pkg/csslib/lib/src/tree_printer.dart
index 8c394766f008acb4c42c3569268acd4d5f339bd9..0604b478d3e9ccaf71511944d23c72f08d26898e 100644
--- a/pkg/csslib/lib/src/tree_printer.dart
+++ b/pkg/csslib/lib/src/tree_printer.dart
@@ -129,9 +129,9 @@ class _TreePrinter extends Visitor {
 
   void visitStyletDirective(StyletDirective node) {
     heading('StyletDirective', node);
-    output.writeValue('dartClassName', node._dartClassName);
+    output.writeValue('dartClassName', node.dartClassName);
     output.depth++;
-    output.writeNodeList('rulesets', node._rulesets);
+    output.writeNodeList('rulesets', node.rulesets);
     output.depth--;
   }
 
@@ -199,7 +199,7 @@ class _TreePrinter extends Visitor {
   void visitDeclarationGroup(DeclarationGroup node) {
     heading('DeclarationGroup', node);
     output.depth++;
-    output.writeNodeList('declarations', node._declarations);
+    output.writeNodeList('declarations', node.declarations);
     output.depth--;
   }
 
@@ -207,7 +207,7 @@ class _TreePrinter extends Visitor {
     heading('MarginGroup', node);
     output.depth++;
     output.writeValue('@directive', node.margin_sym);
-    output.writeNodeList('declarations', node._declarations);
+    output.writeNodeList('declarations', node.declarations);
     output.depth--;
   }