Allow getters to return Intl messages

pkg/intl/lib/extract_messages.dart

Index: pkg/intl/lib/extract_messages.dart
diff --git a/pkg/intl/lib/extract_messages.dart b/pkg/intl/lib/extract_messages.dart
index 0679ff873c6a9ec09b52a64c869dbfec7bd04319..2a34a4330c38c950fb0c5e527364d2bc5db04a4b 100644
--- a/pkg/intl/lib/extract_messages.dart
+++ b/pkg/intl/lib/extract_messages.dart
@@ -147,6 +147,7 @@ class MessageFindingVisitor extends GeneralizingASTVisitor {
    */
   void visitMethodDeclaration(MethodDeclaration node) {
     parameters = node.parameters;
+    if (parameters == null) parameters = new FormalParameterList();
     name = node.name.name;
     super.visitMethodDeclaration(node);
   }
@@ -157,6 +158,7 @@ class MessageFindingVisitor extends GeneralizingASTVisitor {
    */
   void visitFunctionDeclaration(FunctionDeclaration node) {
     parameters = node.functionExpression.parameters;
+    if (parameters == null) parameters = new FormalParameterList();
     name = node.name.name;
     super.visitFunctionDeclaration(node);
   }