Changed @domName annotation in comment to full fledge @DomName annotation.

sdk/lib/html/html_common/metadata.dart

Index: sdk/lib/html/html_common/metadata.dart
diff --git a/sdk/lib/html/html_common/metadata.dart b/sdk/lib/html/html_common/metadata.dart
index d1b2c41d15a9d13005972f207cfb47feded7ea80..02502ff076359bc52be8d56bf756f71b256259eb 100644
--- a/sdk/lib/html/html_common/metadata.dart
+++ b/sdk/lib/html/html_common/metadata.dart
@@ -40,3 +40,16 @@ class SupportedBrowser {
 class Experimental {
   const Experimental();
 }
+
+
+/**
+ * Metadata that specifies the DOM name associated with the element.
+ *
+ * This is used for API generation.
+ *
+ * [name] should be formatted as `interface.member`.
+ */
+class DomName {
+  final String name;
+  const DomName(this.name);
+}