Move DomProxyMixin to this package

R=sigmund@google.com

Review URL: https://codereview.chromium.org//1091903002

CHANGELOG.md

@@ -1,3 +1,23 @@
+#### 0.11.2
+  * Copied `DomProxyMixin` from `custom_element_apigen` to this package and
+    renamed it `CustomElementProxyMixin`. This can be mixed into any class that
+    is using the `@CustomElementProxy` annotation and provides easy access to
+    the underlying javascript element via the `jsElement` getter. For instance
+    the following is a simple example of a dart class that wraps a custom
+    javascript element `foo-element` with a method `doFoo` and a property `foo`.
+
+        @CustomElementProxy('foo-element')
+        class FooElement extends HtmlElement with CustomElementProxyMixin {
+          FooElement.created() : super.created();
+
+          void doFoo(int arg1) => jsElement.callMethod('doFoo', [arg1]);
+
+          int get foo => jsElement['foo'];
+          void set foo(int newFoo) {
+            jsElement['foo'] = newFoo;
+          }
+        }
+
 #### 0.11.1+3
   * Switch `html5lib` package dependency to `html`.
 

lib/build/mirrors_remover.dart

@@ -17,9 +17,9 @@ class MirrorsRemoverTransformer extends Transformer {
   @override
   Future apply(Transform transform) async {
     String source = await transform.primaryInput.readAsString();
-    source = source.replaceAll(
-        'mirror_initializer.dart', 'static_initializer.dart');
-    transform.addOutput(
-        new Asset.fromString(transform.primaryInput.id, source));
+    source =
+        source.replaceAll('mirror_initializer.dart', 'static_initializer.dart');
+    transform
+        .addOutput(new Asset.fromString(transform.primaryInput.id, source));
   }
 }

lib/custom_element_proxy.dart

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 library web_components.custom_element_proxy;
 
+import 'dart:js' as js;
 import 'package:initialize/initialize.dart';
 import 'interop.dart';
 
@@ -22,3 +23,17 @@ class CustomElementProxy implements Initializer<Type> {
     registerDartType(tagName, t, extendsTag: extendsTag);
   }
 }
+
+/// A simple mixin to make it easier to interoperate with the Javascript API of
+/// a browser object. This is mainly used by classes that expose a Dart API for
+/// Javascript custom elements.
+class CustomElementProxyMixin {
+  js.JsObject _proxy;
+
+  js.JsObject get jsElement {
+    if (_proxy == null) {
+      _proxy = new js.JsObject.fromBrowserObject(this);
+    }
+    return _proxy;
+  }
+}

lib/src/init.dart

@@ -23,8 +23,9 @@ Future initWebComponents({List<Type> typeFilter, InitializerFilter customFilter,
   if (typeFilter != null || customFilter != null) {
     return init.run(typeFilter: typeFilter, customFilter: customFilter);
   } else {
-    return init.run(typeFilter: [HtmlImport])
-      .then((_) => init.run(typeFilter: [CustomElement, CustomElementProxy]))
-      .then((_) => initAll ? init.run() : null);
+    return init
+        .run(typeFilter: [HtmlImport])
+        .then((_) => init.run(typeFilter: [CustomElement, CustomElementProxy]))
+        .then((_) => initAll ? init.run() : null);
   }
 }

pubspec.yaml

@@ -1,5 +1,5 @@
 name: web_components
-version: 0.11.1+3
+version: 0.11.2
 author: Polymer.dart Authors <web-ui-dev@dartlang.org>
 homepage: https://www.dartlang.org/polymer-dart/
 description: >