diff --git a/closure.log b/closure.log
index aafe05f9ac..0d8578eca4 100644
--- a/closure.log
+++ b/closure.log
@@ -1262,7 +1262,7 @@ Found    : Element
       let parts = this.split(path);
                   ^^^^
 
-/polymer.html_script_8.js:117: WARNING - Function this._attributeToProperty: called with 2 argument(s). Function requires at least 3 argument(s) and at most 3.
+/polymer.html_script_8.js:110: WARNING - Function this._attributeToProperty: called with 2 argument(s). Function requires at least 3 argument(s) and at most 3.
           this._attributeToProperty(name, value);
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
@@ -1342,39 +1342,39 @@ Found    : Node{$:Object{}, __noInsertionPoint:boolean, nodeList:Array<?>}
         return dom;
         ^^^^^^^^^^^
 
-externs/closure-types.js:375: WARNING - property connectedCallback not defined on any supertype of Polymer_ElementMixin
+externs/closure-types.js:378: WARNING - property connectedCallback not defined on any supertype of Polymer_ElementMixin
 Polymer_ElementMixin.prototype.connectedCallback = function(){};
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-externs/closure-types.js:379: WARNING - property disconnectedCallback not defined on any supertype of Polymer_ElementMixin
+externs/closure-types.js:382: WARNING - property disconnectedCallback not defined on any supertype of Polymer_ElementMixin
 Polymer_ElementMixin.prototype.disconnectedCallback = function(){};
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-externs/closure-types.js:399: WARNING - property attributeChangedCallback not defined on any supertype of Polymer_ElementMixin
+externs/closure-types.js:402: WARNING - property attributeChangedCallback not defined on any supertype of Polymer_ElementMixin
 Polymer_ElementMixin.prototype.attributeChangedCallback = function(name, old, value){};
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-externs/closure-types.js:733: WARNING - property mutableData on interface Polymer_OptionalMutableData is not implemented by type OptionalMutableData
+externs/closure-types.js:736: WARNING - property mutableData on interface Polymer_OptionalMutableData is not implemented by type OptionalMutableData
 Polymer_OptionalMutableData.prototype.mutableData;
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-externs/closure-types.js:747: WARNING - property items on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
+externs/closure-types.js:750: WARNING - property items on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
 Polymer_ArraySelectorMixin.prototype.items;
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-externs/closure-types.js:750: WARNING - property multi on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
+externs/closure-types.js:753: WARNING - property multi on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
 Polymer_ArraySelectorMixin.prototype.multi;
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-externs/closure-types.js:753: WARNING - property selected on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
+externs/closure-types.js:756: WARNING - property selected on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
 Polymer_ArraySelectorMixin.prototype.selected;
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-externs/closure-types.js:756: WARNING - property selectedItem on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
+externs/closure-types.js:759: WARNING - property selectedItem on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
 Polymer_ArraySelectorMixin.prototype.selectedItem;
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-externs/closure-types.js:759: WARNING - property toggle on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
+externs/closure-types.js:762: WARNING - property toggle on interface Polymer_ArraySelectorMixin is not implemented by type ArraySelectorMixin
 Polymer_ArraySelectorMixin.prototype.toggle;
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/externs/closure-types.js b/externs/closure-types.js
index 0641bc943a..641c231c11 100644
--- a/externs/closure-types.js
+++ b/externs/closure-types.js
@@ -143,6 +143,9 @@ Polymer_TemplateStamp.prototype._removeEventListenerFromNode = function(node, ev
 */
 function Polymer_PropertyEffects(){}
 /**
+*/
+Polymer_PropertyEffects.prototype._initializeProperties = function(){};
+/**
 * @override
 * @param {*} props
 */
diff --git a/lib/mixins/property-accessors.html b/lib/mixins/property-accessors.html
index 9da61d5922..5fba0e85ea 100644
--- a/lib/mixins/property-accessors.html
+++ b/lib/mixins/property-accessors.html
@@ -117,13 +117,6 @@
 
       constructor() {
         super();
-        this.__serializing = false;
-        this.__dataCounter = 0;
-        this.__dataInitialized = false;
-        this.__dataInvalid = false;
-        this.__data = {};
-        this.__dataPending = null;
-        this.__dataOld = null;
         this._initializeProperties();
       }
 
@@ -142,6 +135,13 @@
        * @protected
        */
       _initializeProperties() {
+        this.__serializing = false;
+        this.__dataCounter = 0;
+        this.__dataInitialized = false;
+        this.__dataInvalid = false;
+        this.__data = {};
+        this.__dataPending = null;
+        this.__dataOld = null;
         if (this.__dataProto) {
           this._initializeProtoProperties(this.__dataProto);
           this.__dataProto = null;
diff --git a/lib/mixins/property-effects.html b/lib/mixins/property-effects.html
index 2d1e18536f..3174667eff 100644
--- a/lib/mixins/property-effects.html
+++ b/lib/mixins/property-effects.html
@@ -1073,8 +1073,8 @@
         return TYPES;
       }
 
-      constructor() {
-        super();
+      _initializeProperties() {
+        super._initializeProperties();
         this.__dataPendingClients = null;
         this.__dataToNotify = null;
         this.__dataLinkedPaths = null;