Identify the name of the prototype extended by out-of-app custom elements

pkg/web_components/lib/dart_support.js

 // Copyright (c) 2014, 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.
 
 // Teaches dart2js about the wrapping that is done by the Shadow DOM polyfill.
 (function() {
   var ShadowDOMPolyfill = window.ShadowDOMPolyfill;
   if (!ShadowDOMPolyfill) return;
 
   if (navigator.userAgent.indexOf('(Dart)') !== -1) {
@@ skipping 98 matching lines @@
     if (!upgrader) return;
     name = name.toLowerCase();
     var existing = upgraders[name];
     if (existing) {
       console.error('Already have a Dart type associated with ' + name);
       return;
     }
     upgraders[name] = upgrader;
   }
 
+  // dartNativeDispatchHooksTransformer is described on initHooks() in
+  // sdk/lib/_internal/lib/native_helper.dart.
+  if (typeof window.dartNativeDispatchHooksTransformer == 'undefined')
+    window.dartNativeDispatchHooksTransformer = [];
+
+  window.dartNativeDispatchHooksTransformer.push(function(hooks) {

[Siggi Cherem (dart-lang), 2014/06/11 19:34:57]

should we also check for !!ShadowDOMPOlyfill?

Seems that we don't need to use this hook if we already have the other hook
above.

[sra1, 2014/06/11 19:43:24]

Done.

+    var originalGetUnknownTag = hooks.getUnknownTag;
+    hooks.getUnknownTag = function(o, tag) {
+      // Custom elements outside the app in chrome have a constructor
+      // names like "x-b".

[Siggi Cherem (dart-lang), 2014/06/11 19:34:57]

nit: say x-tag instead of x-b (more commonly used for comments :-))

[sra1, 2014/06/11 19:43:24]

Done.

+      if (/-/.test(tag)) {
+        var s = Object.prototype.toString.call(o);
+        var match = s.match(/^\[object ([A-Za-z]*)\]$/);

[Siggi Cherem (dart-lang), 2014/06/11 19:34:57]

let's add Element in the regex

[sra1, 2014/06/11 19:43:24]

Done.

+        if (match) {
+          var name = match[1];
+          if (name != "Object") return name;
+        }
+        return originalGetUnknownTag(o, tag);
+      }
+    };
+  });
+
   doc._registerDartTypeUpgrader = registerDartTypeUpgrader;
   doc.registerElement = registerElement;
 })(document);