--- a/dom/contacts/ContactManager.js
+++ b/dom/contacts/ContactManager.js
@@ -24,19 +24,19 @@ XPCOMUtils.defineLazyServiceGetter(this,
                                    "nsIPermissionManager");
 
 XPCOMUtils.defineLazyServiceGetter(this, "cpmm",
                                    "@mozilla.org/childprocessmessagemanager;1",
                                    "nsIMessageSender");
 
 const CONTACTS_SENDMORE_MINIMUM = 5;
 
-function ContactAddress() { }
+function ContactAddressImpl() { }
 
-ContactAddress.prototype = {
+ContactAddressImpl.prototype = {
   // This function is meant to be called via bindings code for type checking,
   // don't call it directly. Instead, create a content object and call initialize
   // on that.
   initialize: function(aType, aStreetAddress, aLocality, aRegion, aPostalCode, aCountryName, aPref) {
     this.type = aType;
     this.streetAddress = aStreetAddress;
     this.locality = aLocality;
     this.region = aRegion;
@@ -69,19 +69,19 @@ ContactAddress.prototype = {
     return json;
   },
 
   classID: Components.ID("{9cbfa81c-bcab-4ca9-b0d2-f4318f295e33}"),
   contractID: "@mozilla.org/contactAddress;1",
   QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports]),
 };
 
-function ContactField() { }
+function ContactFieldImpl() { }
 
-ContactField.prototype = {
+ContactFieldImpl.prototype = {
   // This function is meant to be called via bindings code for type checking,
   // don't call it directly. Instead, create a content object and call initialize
   // on that.
   initialize: function(aType, aValue, aPref) {
     this.type = aType;
     this.value = aValue;
     this.pref = aPref;
   },
@@ -102,19 +102,19 @@ ContactField.prototype = {
     return json;
   },
 
   classID: Components.ID("{ad19a543-69e4-44f0-adfa-37c011556bc1}"),
   contractID: "@mozilla.org/contactField;1",
   QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports]),
 };
 
-function ContactTelField() { }
+function ContactTelFieldImpl() { }
 
-ContactTelField.prototype = {
+ContactTelFieldImpl.prototype = {
   // This function is meant to be called via bindings code for type checking,
   // don't call it directly. Instead, create a content object and call initialize
   // on that.
   initialize: function(aType, aValue, aCarrier, aPref) {
     this.type = aType;
     this.value = aValue;
     this.carrier = aCarrier;
     this.pref = aPref;
@@ -139,20 +139,16 @@ ContactTelField.prototype = {
   },
 
   classID: Components.ID("{4d42c5a9-ea5d-4102-80c3-40cc986367ca}"),
   contractID: "@mozilla.org/contactTelField;1",
   QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports]),
 };
 
 function validateArrayField(data, createCb) {
-  function isVanillaObj(aObj) {
-    return Object.prototype.toString.call(aObj) == "[object Object]";
-  }
-
   // We use an array-like Proxy to validate data set by content, since we don't
   // have WebIDL arrays yet. See bug 851726.
 
   // ArrayPropertyExposedPropsProxy is used to return "rw" for any valid index
   // and "length" in __exposedProps__.
   const ArrayPropertyExposedPropsProxy = new Proxy({}, {
     get: function(target, name) {
       // Test for index access
@@ -179,19 +175,17 @@ function validateArrayField(data, create
       return target[name];
     }
   };
 
   if (data) {
     data = Array.isArray(data) ? data : [data];
     let filtered = [];
     for (let obj of data) {
-      if (isVanillaObj(obj)) {
-        filtered.push(createCb(obj));
-      }
+      filtered.push(createCb(obj));
     }
     if (filtered.length === 0) {
       return undefined;
     }
     return new Proxy(filtered, ArrayPropertyHandler);
   }
   return undefined;
 }
@@ -209,74 +203,79 @@ const TELFIELD_PROPERTIES = ["tel"];
 
 function Contact() { }
 
 Contact.prototype = {
   // We need to create the content interfaces in these setters, otherwise when
   // we return these objects (e.g. from a find call), the values in the array
   // will be COW's, and content cannot see the properties.
   set email(aEmail) {
-    this._email = validateArrayField(aEmail, function(email) {
-      let obj = new this._window.ContactField();
+    this._email = aEmail;
+  },
+
+  get email() {
+    this._email = validateArrayField(this._email, function(email) {
+      let obj = this._window.ContactField._create(this._window, new ContactFieldImpl());
       obj.initialize(email.type, email.value, email.pref);
       return obj;
     }.bind(this));
-  },
-
-  get email() {
     return this._email;
   },
 
   set adr(aAdr) {
-    this._adr = validateArrayField(aAdr, function(adr) {
-      let obj = new this._window.ContactAddress();
+    this._adr = aAdr;
+  },
+
+  get adr() {
+    this._adr = validateArrayField(this._adr, function(adr) {
+      let obj = this._window.ContactAddress._create(this._window, new ContactAddressImpl());
       obj.initialize(adr.type, adr.streetAddress, adr.locality,
                      adr.region, adr.postalCode, adr.countryName,
                      adr.pref);
       return obj;
     }.bind(this));
-  },
-
-  get adr() {
     return this._adr;
   },
 
   set tel(aTel) {
-    this._tel = validateArrayField(aTel, function(tel) {
-      let obj = new this._window.ContactTelField();
+    this._tel = aTel;
+  },
+
+  get tel() {
+    this._tel = validateArrayField(this._tel, function(tel) {
+      let obj = this._window.ContactTelField._create(this._window, new ContactTelFieldImpl());
       obj.initialize(tel.type, tel.value, tel.carrier, tel.pref);
       return obj;
     }.bind(this));
-  },
-
-  get tel() {
     return this._tel;
   },
 
   set impp(aImpp) {
-    this._impp = validateArrayField(aImpp, function(impp) {
-      let obj = new this._window.ContactField();
+    this._impp = aImpp;
+  },
+
+  get impp() {
+    this._impp = validateArrayField(this._impp, function(impp) {
+      let obj = this._window.ContactField._create(this._window, new ContactFieldImpl());
       obj.initialize(impp.type, impp.value, impp.pref);
       return obj;
     }.bind(this));
-  },
-
-  get impp() {
     return this._impp;
   },
 
   set url(aUrl) {
-    this._url = validateArrayField(aUrl, function(url) {
-      let obj = new this._window.ContactField();
+    this._url = aUrl;
+  },
+
+  get url() {
+    this._url = validateArrayField(this._url, function(url) {
+      let obj = this._window.ContactField._create(this._window, new ContactFieldImpl());
       obj.initialize(url.type, url.value, url.pref);
       return obj;
     }.bind(this));
-  },
-
-  get url() {
     return this._url;
   },
 
   init: function(aWindow) {
     this._window = aWindow;
   },
 
   __init: function(aProp) {
@@ -612,41 +611,41 @@ ContactManager.prototype = {
       }
     }
 
     for (let prop of ADDRESS_PROPERTIES) {
       if (aContact[prop]) {
         newContact.properties[prop] = [];
         for (let i of aContact[prop]) {
           if (i) {
-            let json = ContactAddress.prototype.toJSON.apply(i, [true]);
+            let json = ContactAddressImpl.prototype.toJSON.apply(i, [true]);
             newContact.properties[prop].push(json);
           }
         }
       }
     }
 
     for (let prop of FIELD_PROPERTIES) {
       if (aContact[prop]) {
         newContact.properties[prop] = [];
         for (let i of aContact[prop]) {
           if (i) {
-            let json = ContactField.prototype.toJSON.apply(i, [true]);
+            let json = ContactFieldImpl.prototype.toJSON.apply(i, [true]);
             newContact.properties[prop].push(json);
           }
         }
       }
     }
 
     for (let prop of TELFIELD_PROPERTIES) {
       if (aContact[prop]) {
         newContact.properties[prop] = [];
         for (let i of aContact[prop]) {
           if (i) {
-            let json = ContactTelField.prototype.toJSON.apply(i, [true]);
+            let json = ContactTelFieldImpl.prototype.toJSON.apply(i, [true]);
             newContact.properties[prop].push(json);
           }
         }
       }
     }
 
     let request = this.createRequest();
     let requestID = this.getRequestId({request: request, reason: reason});
@@ -817,10 +816,10 @@ ContactManager.prototype = {
 
   classID: Components.ID("{8beb3a66-d70a-4111-b216-b8e995ad3aff}"),
   contractID: "@mozilla.org/contactManager;1",
   QueryInterface: XPCOMUtils.generateQI([Ci.nsISupportsWeakReference,
                                          Ci.nsIDOMGlobalPropertyInitializer]),
 };
 
 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([
-  Contact, ContactManager, ContactAddress, ContactField, ContactTelField
+  Contact, ContactManager, ContactFieldImpl, ContactAddressImpl, ContactTelFieldImpl
 ]);