diff --git a/src/lib/base.html b/src/lib/base.html
index 4f557b9eb2..42d54ae7d9 100644
--- a/src/lib/base.html
+++ b/src/lib/base.html
@@ -46,6 +46,7 @@
         }
       } else {
         this._desugarBehaviors(); // abstract
+        // previously factor behavior call unrolled for perf
         for (var i=0, b; i < this.behaviors.length; i++) {
           b = this.behaviors[i];
           if (b.beforeRegister) {
@@ -68,6 +69,7 @@
       }
       Polymer.telemetry.instanceCount++;
       this.root = this;
+      // previously factor behavior call unrolled for perf
       for (var i=0, b; i < this.behaviors.length; i++) {
         b = this.behaviors[i];
         if (b.created) {
@@ -97,6 +99,7 @@
         // IFF `lazyRegister` is 'max'
         if (settings.lazyRegister === 'max') {
           proto._desugarBehaviors(); // abstract
+          // previously factor behavior call unrolled for perf
           for (var i=0, b; i < proto.behaviors.length; i++) {
             b = proto.behaviors[i];
             if (b.beforeRegister) {
@@ -109,6 +112,7 @@
           proto._finishRegisterFeatures();
         }
         // registration extension point
+        // previously factor behavior call unrolled for perf
         for (var j=0, pb; j < proto.behaviors.length; j++) {
           pb = proto.behaviors[j];
           if (pb.registered) {
@@ -135,6 +139,7 @@
       var self = this;
       Polymer.RenderStatus.whenReady(function() {
         self.isAttached = true;
+        // previously factor behavior call unrolled for perf
         for (var i=0, b; i < self.behaviors.length; i++) {
           b = self.behaviors[i];
           if (b.attached) {
@@ -153,6 +158,7 @@
       var self = this;
       Polymer.RenderStatus.whenReady(function() {
         self.isAttached = false;
+        // previously factor behavior call unrolled for perf
         for (var i=0, b; i < self.behaviors.length; i++) {
           b = self.behaviors[i];
           if (b.detached) {
@@ -170,6 +176,7 @@
       // TODO(sorvell): consider filtering out changes to host attributes
       // note: this was barely measurable with 3 host attributes.
       this._attributeChangedImpl(name); // abstract
+      // previously factor behavior call unrolled for perf
       for (var i=0, b; i < this.behaviors.length; i++) {
         b = this.behaviors[i];
         if (b.attributeChanged) {
diff --git a/src/lib/dom-module.html b/src/lib/dom-module.html
index 5a78115919..3efcb3b23a 100644
--- a/src/lib/dom-module.html
+++ b/src/lib/dom-module.html
@@ -84,7 +84,7 @@
   });
 
   Object.defineProperty(DomModule.prototype, 'constructor', {
-    value: DomModule, configurable: true
+    value: DomModule, configurable: true, writable: true
   });
 
   // NOTE: HTMLImports polyfill does not
diff --git a/src/micro/behaviors.html b/src/micro/behaviors.html
index 8cc51a48c8..da92c02ab1 100644
--- a/src/micro/behaviors.html
+++ b/src/micro/behaviors.html
@@ -101,10 +101,10 @@
 
     _mixinBehavior: function(b) {
       var n$ = Object.getOwnPropertyNames(b);
-      var skipDefine = b._skipDefineProperty;
+      var useAssignment = b._noAccessors;
       for (var i=0, n; (i<n$.length) && (n=n$[i]); i++) {
         if (!Polymer.Base._behaviorProperties[n] && !this.hasOwnProperty(n)) {
-          if (skipDefine) {
+          if (useAssignment) {
             this[n] = b[n];
           } else {
             this.copyOwnProperty(n, b, this);
@@ -128,27 +128,6 @@
       this._prepBehavior(this);
     },
 
-    _doBehavior: function(name, args) {
-      for (var i=0; i < this.behaviors.length; i++) {
-        this._invokeBehavior(this.behaviors[i], name, args);
-      }
-      this._invokeBehavior(this, name, args);
-    },
-
-    // note: repeating logic here to avoid fn call.
-    _doBehaviorOnly: function(name, args) {
-      for (var i=0; i < this.behaviors.length; i++) {
-        this._invokeBehavior(this.behaviors[i], name, args);
-      }
-    },
-
-    _invokeBehavior: function(b, name, args) {
-      var fn = b[name];
-      if (fn) {
-        fn.apply(this, args || Polymer.nar);
-      }
-    },
-
     _marshalBehaviors: function() {
       for (var i=0; i < this.behaviors.length; i++) {
         this._marshalBehavior(this.behaviors[i]);
@@ -173,7 +152,7 @@
     detached: true,
     attributeChanged: true,
     ready: true,
-    _skipDefineProperty: true
+    _noAccessors: true
   }
 
 </script>
diff --git a/test/unit/base.html b/test/unit/base.html
index 3f14997256..a4ec52ec4e 100644
--- a/test/unit/base.html
+++ b/test/unit/base.html
@@ -37,11 +37,6 @@
   Child._setAttributeToProperty = function() {};
   Child.behaviors = [];
   Child._desugarBehaviors = function() {};
-  Child._doBehavior = function(name, args) {
-    if (this[name]) {
-      this[name].apply(this, args || []);
-    }
-  };
   instance = Object.create(Child);
   // make __proto__ work on IE10.
   if (!Object.__proto__) {