Avoid copying certain properties from behaviors

This better matches what Polymer 1.x did for:
* hostAttributes
* listeners
* properties
* observers

lib/legacy/class.html

@@ -14,7 +14,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
 
     'use strict';
 
-    const metaProps = {
+    const lifecycleProps = {
       attached: true,
       detached: true,
       ready: true,
@@ -22,18 +22,29 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
       beforeRegister: true,
       registered: true,
       attributeChanged: true,
-    };
-
-    const excludeProps = Object.assign({
-      behaviors: true
-    }, metaProps);
-
-    const lifecycleProps = Object.assign({
       listeners: true,
       hostAttributes: true
-    }, metaProps);
+    };
 
-    function copyProperties(source, target) {
+    const excludeOnInfo = {
+      attached: true,
+      detached: true,
+      ready: true,
+      created: true,
+      beforeRegister: true,
+      registered: true,
+      attributeChanged: true,
+      behaviors: true
+    };
+
+    const excludeOnBehaviors = Object.assign({
+      listeners: true,
+      hostAttributes: true,
+      properties: true,
+      observers: true,
+    }, excludeOnInfo);
+
+    function copyProperties(source, target, excludeProps) {
       for (let p in source) {
         // NOTE: cannot copy `excludeProps` methods onto prototype at least because
         // `super.ready` must be called and is not included in the user fn.
@@ -97,12 +108,12 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     // (again same as 1.x)
     function applyBehaviors(proto, behaviors, lifecycle) {
       for (let i=0; i<behaviors.length; i++) {
-        applyInfo(proto, behaviors[i], lifecycle);
+        applyInfo(proto, behaviors[i], lifecycle, excludeOnBehaviors);
       }
     }
 
-    function applyInfo(proto, info, lifecycle) {
-      copyProperties(info, proto);
+    function applyInfo(proto, info, lifecycle, excludeProps) {
+      copyProperties(info, proto, excludeProps);
       for (let p in lifecycleProps) {
         if (info[p]) {
           lifecycle[p] = lifecycle[p] || [];
@@ -282,7 +293,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
           if (behaviorList) {
             applyBehaviors(proto, behaviorList, lifecycle);
           }
-          applyInfo(proto, info, lifecycle);
+          applyInfo(proto, info, lifecycle, excludeOnInfo);
           let list = lifecycle.beforeRegister;
           if (list) {
             for (let i=0; i < list.length; i++) {