Dartium JS Enabled take 2

tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate

Index: tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate b/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
index 3d9e6afb5cedefa436b006eb0483131cdaea4545..bf8f0ffc2c5ef6293eeff7f52d9889876db75987 100644
--- a/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
+++ b/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
@@ -17,7 +17,7 @@ $else
   BodyElement get body => _body;
 
   @DomName('Document.body')
-  void set body(BodyElement value) {
+  set body(BodyElement value) {
     _body = value;
   }
 $endif
@@ -90,7 +90,7 @@ $endif
 
   @DomName('Document.selectedStylesheetSet')
   String get selectedStylesheetSet => _selectedStylesheetSet;
-  void set selectedStylesheetSet(String value) {
+  set selectedStylesheetSet(String value) {
     _selectedStylesheetSet = value;
   }
 
@@ -101,7 +101,7 @@ $endif
   String get title => _title;
 
   @DomName('Document.title')
-  void set title(String value) {
+  set title(String value) {
     _title = value;
   }
 
@@ -187,6 +187,41 @@ $if DART2JS
 $else
   String get visibilityState => _webkitVisibilityState;
 $endif
+$if DARTIUM
+
+  /**
+   * Internal routine to find the DOM JS class name being extended for custom
+   * elements.
+   */
+  String _getJSClassName(ClassMirror classMirror) {
+    var jsClassName = null;
+    var isElement = false;
+
+    while (classMirror.superclass != null) {
+      var fullName = classMirror.superclass.qualifiedName;
+      isElement = isElement || (fullName == #dart.dom.html.Element);
+
+      var domLibrary = MirrorSystem.getName(fullName).startsWith('dart.dom.');
+      if (jsClassName == null && domLibrary) {
+        // Lookup JS class name (if not found).
+        var metadatas = classMirror.metadata;
+        for (var metadata in metadatas) {
+          var metaDataMirror = metadata.reflectee;
+          var metaType = reflectClass(metaDataMirror.runtimeType);
+          if (MirrorSystem.getName(metaType.simpleName) == 'DomName' &&
+              metaDataMirror.name.startsWith('HTML')) {
+            jsClassName = metadata.reflectee.name;
+          }
+        }
+      }
+
+      classMirror = classMirror.superclass;
+    }
+
+    // If we're an element then everything is okay.
+    return isElement ? jsClassName : null;
+  }
+$endif
 
   @Experimental()
   /**
@@ -236,7 +271,73 @@ $if DART2JS
     _registerCustomElement(JS('', 'window'), this, tag, customElementClass,
         extendsTag);
 $else
-    _Utils.register(this, tag, customElementClass, extendsTag);
+    // TODO(terry): Need to handle the extendsTag.
+
+    // Figure out which DOM class is being extended from the user's Dart class.
+    var classMirror = reflectClass(customElementClass);
+    var jsClassName = _getJSClassName(classMirror);
+    if (jsClassName == null) {
+      // Only components derived from HTML* can be extended.
+      throw new DomException.jsInterop("HierarchyRequestError: Only HTML elements can be customized.");
+    }
+
+    // Start the hookup the JS way create an <x-foo> element that extends the
+    // <x-base> custom element. Inherit its prototype and signal what tag is
+    // inherited:
+    //
+    //     var myProto = Object.create(HTMLElement.prototype);
+    //     var myElement = document.registerElement('x-foo', {prototype: myProto});
+    var baseElement = js.context[jsClassName];
+    if (baseElement == null) {
+      // Couldn't find the HTML element so use a generic one.
+      baseElement = js.context['HTMLElement'];
+    }
+    var elemProto = js.context['Object'].callMethod("create", [baseElement['prototype']]);
+
+    // TODO(terry): Hack to stop recursion re-creating custom element when the
+    //              created() constructor of the custom element does e.g.,
+    //
+    //                  MyElement.created() : super.created() {
+    //                    this.innerHtml = "<b>I'm an x-foo-with-markup!</b>";
+    //                  }
+    //
+    //              sanitizing causes custom element to created recursively
+    //              until stack overflow.
+    //
+    //              See https://github.com/dart-lang/sdk/issues/23666
+    int creating = 0;
+    elemProto['createdCallback'] = new js.JsFunction.withThis(($this) {
+      if (_getJSClassName(reflectClass(customElementClass).superclass) != null && creating < 2) {
+        creating++;
+
+        var dartClass = _blink.Blink_Utils.constructElement(customElementClass, $this);
+
+        // Need to remember the Dart class that was created for this custom so
+        // return it and setup the blink_jsObject to the $this that we'll be working
+        // with as we talk to blink. 
+        $this['dart_class'] = dartClass;
+
+        creating--;
+      }
+    });
+    elemProto['attributeChangedCallback'] = new js.JsFunction.withThis(($this, attrName, oldVal, newVal) {
+      if ($this["dart_class"] != null && $this['dart_class'].attributeChanged != null) {
+        $this['dart_class'].attributeChanged(attrName, oldVal, newVal);
+      }
+    });
+    elemProto['attachedCallback'] = new js.JsFunction.withThis(($this) {
+      if ($this["dart_class"] != null && $this['dart_class'].attached != null) {
+        $this['dart_class'].attached();
+      }
+    });
+    elemProto['detachedCallback'] = new js.JsFunction.withThis(($this) {
+      if ($this["dart_class"] != null && $this['dart_class'].detached != null) {
+        $this['dart_class'].detached();
+      }
+    });
+    // document.registerElement('x-foo', {prototype: elemProto, extends: extendsTag});
+    var jsMap = new js.JsObject.jsify({'prototype': elemProto, 'extends': extendsTag});
+    js.context['document'].callMethod('registerElement', [tag, jsMap]);
 $endif
   }