Update all Angular libs (run update_all.sh).

third_party/pkg/angular/lib/formatter/stringify.dart

Index: third_party/pkg/angular/lib/formatter/stringify.dart
diff --git a/third_party/pkg/angular/lib/formatter/stringify.dart b/third_party/pkg/angular/lib/formatter/stringify.dart
new file mode 100644
index 0000000000000000000000000000000000000000..439bfc64583a79f470a9ce178767cb5b433fc6cd
--- /dev/null
+++ b/third_party/pkg/angular/lib/formatter/stringify.dart
@@ -0,0 +1,16 @@
+part of angular.formatter_internal;
+
+/**
+ * Allows you to convert an object to a string.
+ *
+ * Null object are converted to an empty string.
+ *
+ *
+ * Usage:
+ *
+ *     {{ expression | stringify }}
+ */
+@Formatter(name:'stringify')
+class Stringify implements Function {
+  String call(obj) => obj == null ? "" : obj.toString();
+}