Add support for custom elements to MDV

tools/dom/src/TemplateBindings.dart

Index: tools/dom/src/TemplateBindings.dart
diff --git a/tools/dom/src/TemplateBindings.dart b/tools/dom/src/TemplateBindings.dart
index 5192927966d7bb961e7fc0b1678305854784cab8..0cc603d369bc0634b37be7824b31c65bc9875d12 100644
--- a/tools/dom/src/TemplateBindings.dart
+++ b/tools/dom/src/TemplateBindings.dart
@@ -523,7 +523,7 @@ void _parseAndBind(Node node, String name, String text, model,
     return newValue.toString();
   };
 
-  node.bind(name, replacementBinding, 'value');
+  _nodeOrCustom(node).bind(name, replacementBinding, 'value');
 }
 
 void _bindOrDelegate(node, name, model, String path,
@@ -537,9 +537,17 @@ void _bindOrDelegate(node, name, model, String path,
     }
   }
 
-  node.bind(name, model, path);
+  _nodeOrCustom(node).bind(name, model, path);
 }
 
+/**
+ * Gets the [node]'s custom [Element.xtag] if present, otherwise returns
+ * the node. This is used so nodes can override [Node.bind], [Node.unbind],
+ * and [Node.unbindAll] like
+ */
+// TODO(jmesserly): remove this when we can extend Element for real.
+_nodeOrCustom(node) => node is Element ? node.xtag : node;

[Siggi Cherem (dart-lang), 2013/05/13 16:42:13]

interesting, what about a custom element that extends from <template>? Seems
like 'bind' in the custom element takes priority, but I wonder if it should be
applied to both?

[Jennifer Messerly, 2013/05/13 19:42:41]

Not sure I understand...

What this does is try and simulate inheriting Element. It needs to be good
enough that we can implement binding to an element's fields. It's definitely not
perfect. You can show the leakiness by simply calling .bind yourself on the
underlying Element; that will skill the custom impl. That's why we need real
inheritance.

It's quite possible something doesn't work if you extend <template> element. I
haven't yet seen a compelling use case for extending template, so I'm inclined
not to put much effort into polyfilling it.

[Jennifer Messerly, 2013/05/13 19:43:45]

oops, "skill the custom impl" should be "skip the custom impl".

+
 class _BindingToken {
   final String value;
   final bool isBinding;
@@ -599,7 +607,7 @@ void _addTemplateInstanceRecord(fragment, model) {
 }
 
 void _removeAllBindingsRecursively(Node node) {
-  node.unbindAll();
+  _nodeOrCustom(node).unbindAll();
   for (var c = node.$dom_firstChild; c != null; c = c.nextNode) {
     _removeAllBindingsRecursively(c);
   }