Prototype of Dart proxies for JS objects.

tools/dom/src/native_DOMImplementation.dart

Index: tools/dom/src/native_DOMImplementation.dart
diff --git a/tools/dom/src/native_DOMImplementation.dart b/tools/dom/src/native_DOMImplementation.dart
index d84e39642d2b70ee6109a3f3526458306b73e5bc..c630c828db5467cf425e15552e67311813cf7033 100644
--- a/tools/dom/src/native_DOMImplementation.dart
+++ b/tools/dom/src/native_DOMImplementation.dart
@@ -394,48 +394,10 @@ class _Utils {
 
   static bool isNoSuchMethodError(obj) => obj is NoSuchMethodError;
 
-  static bool _isBuiltinType(ClassMirror cls) {
-    // TODO(vsm): Find a less hackish way to do this.
-    LibraryMirror lib = cls.owner;
-    String libName = lib.uri.toString();
-    return libName.startsWith('dart:');
-  }
-
   static void register(Document document, String tag, Type type,
       String extendsTagName) {
-    // TODO(vsm): Move these checks into native code.
-    ClassMirror cls = reflectClass(type);
-    if (_isBuiltinType(cls)) {
-      throw new UnsupportedError("Invalid custom element from ${(cls.owner as LibraryMirror).uri}.");
-    }
-    var className = MirrorSystem.getName(cls.simpleName);
-    var createdConstructor = cls.declarations[new Symbol('$className.created')];
-    if (createdConstructor == null ||
-        createdConstructor is! MethodMirror ||
-        !createdConstructor.isConstructor) {
-      throw new UnsupportedError(
-          'Class is missing constructor $className.created');
-    }
+    var nativeClass = _validateCustomType(type);
 
-    if (createdConstructor.parameters.length > 0) {
-      throw new UnsupportedError(
-          'Constructor $className.created must take zero arguments');
-    }
-
-    Symbol objectName = reflectClass(Object).qualifiedName;
-    bool isRoot(ClassMirror cls) =>
-        cls == null || cls.qualifiedName == objectName;
-    Symbol elementName = reflectClass(HtmlElement).qualifiedName;
-    bool isElement(ClassMirror cls) =>
-        cls != null && cls.qualifiedName == elementName;
-    ClassMirror superClass = cls.superclass;
-    ClassMirror nativeClass = _isBuiltinType(superClass) ? superClass : null;
-    while(!isRoot(superClass) && !isElement(superClass)) {
-      superClass = superClass.superclass;
-      if (nativeClass == null && _isBuiltinType(superClass)) {
-        nativeClass = superClass;
-      }
-    }
     if (extendsTagName == null) {
       if (nativeClass.reflectedType != HtmlElement) {
         throw new UnsupportedError('Class must provide extendsTag if base '
@@ -452,6 +414,8 @@ class _Utils {
   static Element createElement(Document document, String tagName) native "Utils_createElement";
 
   static void initializeCustomElement(HtmlElement element) native "Utils_initializeCustomElement";
+
+  static void changeElementWrapper(HtmlElement element, Type type) native "Utils_changeElementWrapper";
 }
 
 class _DOMWindowCrossFrame extends NativeFieldWrapperClass2 implements