Fixed few more issues with upgrader and custom event identitiy

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

Index: tools/dom/templates/html/dartium/html_dartium.darttemplate
diff --git a/tools/dom/templates/html/dartium/html_dartium.darttemplate b/tools/dom/templates/html/dartium/html_dartium.darttemplate
index 25336a7e730db2f92f84b8e941f7189d3943a0de..222865b43a178372775c7fc42d88be8f5e4847e7 100644
--- a/tools/dom/templates/html/dartium/html_dartium.darttemplate
+++ b/tools/dom/templates/html/dartium/html_dartium.darttemplate
@@ -420,8 +420,9 @@ wrap_jso(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.
-      dartClass_instance = jsObject['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 localName = jsObject['localName'];
       var customElementClass = _knownCustomeElements[localName];
@@ -495,6 +496,29 @@ wrap_jso_custom_element(jsObject) {
   }
 }
 
+// Upgrade a Dart HtmlElement to the user's Dart custom element class.
+_upgradeHtmlElement(dartInstance) {
+  var dartInstanceMirror = reflect(dartInstance);
+  if (dartInstanceMirror.type.qualifiedName == #dart.dom.html.HtmlElement) {

[Alan Knight, 2015/10/07 16:21:29]

Could you do this with dartInstance.runtimeType == HtmlElement rather than using
mirrors?

+    // Must be exactly HtmlElement not something derived from it.
+    var jsObject = dartInstance.blink_jsObject;
+    var localName = dartInstance.localName;
+    var customElementClass = _knownCustomeElements[localName];
+    // Custom Element to upgrade.
+    if (customElementClass != null) {
+      try {
+        dartInstance = _blink.Blink_Utils.constructElement(customElementClass, jsObject);
+      } finally {
+        dartInstance.blink_jsObject = jsObject;
+        jsObject['dart_class'] = dartInstance;
+        js.setDartHtmlWrapperFor(jsObject, dartInstance);
+     }
+   }
+  }
+
+  return dartInstance;
+}
+
 class DebugAssertException implements Exception {
   String message;
   DebugAssertException(this.message);