First cut at behaviors. This just implements the lifecycle methodsportion. We may get the rest for …

lib/src/common/polymer_mixin.dart

Index: lib/src/common/polymer_mixin.dart
diff --git a/lib/src/common/polymer_mixin.dart b/lib/src/common/polymer_mixin.dart
index c16678a9432bd39d4b047e650ec8ceb640c55185..b813acd8fd505ca55576ba9dc9a1d923b4ebb1fd 100644
--- a/lib/src/common/polymer_mixin.dart
+++ b/lib/src/common/polymer_mixin.dart
@@ -6,11 +6,12 @@ library polymer.src.common.polymer_js_proxy;
 import 'dart:html';
 import 'dart:js';
 import 'package:polymer_interop/polymer_interop.dart' show Polymer, PolymerDom;
+import 'package:web_components/web_components.dart';
 import 'js_proxy.dart';
 
 
 /// Basic api for re-using the polymer js prototypes.
-abstract class PolymerMixin implements JsProxy {
+abstract class PolymerMixin implements JsProxy, CustomElementProxyMixin {

[Siggi Cherem (dart-lang), 2015/08/12 22:43:15]

not sure I follow - why is this change needed for behaviors?

[jakemac, 2015/08/13 17:50:45]

The js behaviors require an implementation of `CustomElementProxyMixin`, so I
needed to specify this here in order to be able to mix them in (its already
implementing the same api).

   JsObject _proxy;
 
   JsObject get jsElement {