Extension support

tools/dom/templates/html/dartium/html_dartium.darttemplate

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // DO NOT EDIT
 // Auto-generated dart:html library.
 
 /**
  * HTML elements and other resources for web-based applications that need to
  * interact with the browser and the DOM (Document Object Model).
@@ skipping 335 matching lines @@
 }
 
 
 /******************************************************************************
  **********                                                          **********
  **********                    JS Interop Support                    **********
  **********                                                          **********
  ******************************************************************************/
 
 // List of known tagName to DartClass for custom elements, used for upgrade.
-var _knownCustomElements = new Map<String, Type>();
+var _knownCustomElements = new Map<String, Map<Type, String>>();
 
-void _addCustomElementType(String tagName, Type dartClass) {
-  _knownCustomElements[tagName] = dartClass;
+void _addCustomElementType(String tagName, Type dartClass, [String extendTag]) {
+  _knownCustomElements[tagName] = 
+      {'type': dartClass, 'extends': extendTag != null ? extendTag : "" };
 }
 
-Type _getCustomElementType(object) => _knownCustomElements[_getCustomElementName(object)];
+Type _getCustomElementType(object) {
+  var entry = _knownCustomElements[_getCustomElementName(object)];
+  if (entry != null) {
+    return entry['type'];
+  }
+  return null;
+}
+
+String _getCustomElementExtends(object) {
+  var entry = _knownCustomElements[_getCustomElementName(object)];
+  if (entry != null) {
+    return entry['extends'];
+  }
+  return null;
+}
+
+_getCustomElement(object) => _knownCustomElements[_getCustomElementName(object)];
 
 // Return the tag name or is attribute of the custom element or data binding.
 String _getCustomElementName(element) {
   var jsObject;
   var tag = "";
   var runtimeType = element.runtimeType;
   if (runtimeType == HtmlElement) {
     tag = element.localName;
   } else if (runtimeType == TemplateElement) {
     // Data binding with a Dart class.
@@ skipping 108 matching lines @@
       js.setDartHtmlWrapperFor(jsObject, jsObject);
       return jsObject;
     }
 
     var dartClass_instance;
     if (jsObject.hasProperty('dart_class')) {
       // Got a dart_class (it's a custom element) use it it's already set up
       // make sure it's upgraded.
       dartClass_instance = _upgradeHtmlElement(jsObject['dart_class']);
     } else {
-      var customElementClass = _getCustomElementType(jsObject);
+      var customElementClass = null;
+      var extendsTag = "";
+      var custom = _getCustomElement(jsObject);
+      if (custom != null) {
+        customElementClass = custom['type'];
+        extendsTag = custom['extends'];
+      }
       // Custom Element to upgrade.
-      if (jsTypeName == 'HTMLElement' && customElementClass != null) {
+      if (jsTypeName == 'HTMLElement' && customElementClass != null && extendsTag == "") {
         try {
           dartClass_instance = _blink.Blink_Utils.constructElement(customElementClass, jsObject);
         } finally {
           dartClass_instance.blink_jsObject = jsObject;
           jsObject['dart_class'] = dartClass_instance;
           js.setDartHtmlWrapperFor(jsObject, dartClass_instance);
        }
       } else {
         // TODO(terry): Verify with jakemacd that this is right?
         // If we every get an auto-binding we're matching previous non-JS Interop
@@ skipping 261 matching lines @@
 
 unwrap_jso(dartClass_instance) => dartClass_instance;
 wrap_jso(jsObject) => jsObject;
 make_dart_rectangle(r) => r;
 convertDartToNative_Dictionary(Map dict) => dict;
 List convertDartToNative_StringArray(List<String> input) => input;
 convertDartToNative_List(List input) => input;
 createCustomUpgrader(Type customElementClass, $this) => $this;
 
 $endif