--- a/chat/components/public/prplIProtocol.idl
+++ b/chat/components/public/prplIProtocol.idl
@@ -1,16 +1,18 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsISupports.idl"
-#include "nsISimpleEnumerator.idl"
 #include "imIAccount.idl"
 
+interface prplIPref;
+interface prplIUsernameSplit;
+
 [scriptable, uuid(7d302db0-3813-4c51-8372-c7eb5fc9f3d3)]
 interface prplIProtocol: nsISupports {
   /**
    * This method is used so that classes implementing several protocol
    * plugins can know which protocol is desired for this instance.
    *
    * @param aId The prpl id.
    */
@@ -22,24 +24,24 @@ interface prplIProtocol: nsISupports {
   // for the directory name for log storage.
   readonly attribute AUTF8String normalizedName;
 
   // returns a chrome URI pointing to a folder that contains the files:
   // icon.png icon32.png and icon48.png
   readonly attribute AUTF8String iconBaseURI;
 
   /**
-   * @returns an enumerator of prplIPref
+   * @returns an array of prplIPref
    */
-  nsISimpleEnumerator getOptions();
+  Array<prplIPref> getOptions();
 
   /**
-   * @returns an enumerator of prplIUsernameSplit
+   * @returns an array of prplIUsernameSplit
    */
-  nsISimpleEnumerator getUsernameSplit();
+  Array<prplIUsernameSplit> getUsernameSplit();
 
   // descriptive text to put in the username input box when it is empty
   readonly attribute AUTF8String usernameEmptyText;
 
   // Use this function to avoid attempting to create duplicate accounts
   boolean accountExists(in AUTF8String aName);
 
   // These should all be stuff that some plugins can do and others can't.

--- a/chat/components/src/imAccounts.jsm
+++ b/chat/components/src/imAccounts.jsm
@@ -1,17 +1,16 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 var EXPORTED_SYMBOLS = ["AccountsService"];
 
 var {
   ClassInfo,
-  EmptyEnumerator,
   nsSimpleEnumerator,
   XPCOMUtils,
   setTimeout,
   clearTimeout,
   executeSoon,
   l10nHelper,
 } = ChromeUtils.import("resource:///modules/imXPCOMUtils.jsm");
 var { Services } = ChromeUtils.import("resource:///modules/imServices.jsm");
@@ -104,20 +103,20 @@ UnknownProtocol.prototype = {
   },
   get normalizedName() {
     return this.name;
   },
   get iconBaseURI() {
     return "chrome://chat/skin/prpl-unknown/";
   },
   getOptions() {
-    return EmptyEnumerator;
+    return [];
   },
   getUsernameSplit() {
-    return EmptyEnumerator;
+    return [];
   },
   get usernameEmptyText() {
     return "";
   },
 
   getAccount(aKey, aName) {
     throw Components.Exception("", Cr.NS_ERROR_NOT_IMPLEMENTED);
   },

--- a/chat/modules/jsProtoHelper.jsm
+++ b/chat/modules/jsProtoHelper.jsm
@@ -1159,33 +1159,30 @@ var GenericProtocolPrototype = {
   _getOptionDefault(aName) {
     if (this.options && this.options.hasOwnProperty(aName)) {
       return this.options[aName].default;
     }
     throw new Error(aName + " has no default value in " + this.id + ".");
   },
   getOptions() {
     if (!this.options) {
-      return EmptyEnumerator;
+      return [];
     }
 
     let purplePrefs = [];
     for (let [name, option] of Object.entries(this.options)) {
       purplePrefs.push(new purplePref(name, option));
     }
-    return new nsSimpleEnumerator(purplePrefs);
+    return purplePrefs;
   },
   getUsernameSplit() {
     if (!this.usernameSplits || !this.usernameSplits.length) {
-      return EmptyEnumerator;
+      return [];
     }
-
-    return new nsSimpleEnumerator(
-      this.usernameSplits.map(split => new UsernameSplit(split))
-    );
+    return this.usernameSplits.map(split => new UsernameSplit(split));
   },
 
   registerCommands() {
     if (!this.commands) {
       return;
     }
 
     this.commands.forEach(function(command) {

--- a/mail/components/im/content/am-im.js
+++ b/mail/components/im/content/am-im.js
@@ -93,22 +93,16 @@ var account = {
     }
 
     this.prefs = Services.prefs.getBranch(
       "messenger.account." + this.account.id + ".options."
     );
     this.populateProtoSpecificBox();
   },
 
-  *getProtoOptions() {
-    for (let option of this.proto.getOptions()) {
-      yield option;
-    }
-  },
-
   populateProtoSpecificBox() {
     let attributes = {};
     attributes[Ci.prplIPref.typeBool] = [
       { name: "wsm_persist", value: "true" },
       { name: "preftype", value: "bool" },
       { name: "genericattr", value: "true" },
     ];
     attributes[Ci.prplIPref.typeInt] = [
@@ -118,17 +112,17 @@ var account = {
     ];
     attributes[Ci.prplIPref.typeString] = attributes[Ci.prplIPref.typeList] = [
       { name: "wsm_persist", value: "true" },
       { name: "preftype", value: "wstring" },
       { name: "genericattr", value: "true" },
     ];
     let haveOptions = accountOptionsHelper.addOptions(
       "server.",
-      this.getProtoOptions(),
+      this.proto.getOptions(),
       attributes
     );
     let advanced = document.getElementById("advanced");
     if (advanced.hidden && haveOptions) {
       advanced.hidden = false;
       // Force textbox XBL binding attachment by forcing layout,
       // otherwise setFormElementValue from AccountManager.js sets
       // properties that don't exist when restoring values.

--- a/mail/components/im/content/imAccountWizard.js
+++ b/mail/components/im/content/imAccountWizard.js
@@ -174,20 +174,17 @@ var accountWizard = {
     document.getElementById("usernameInfo").textContent = usernameInfo;
 
     var vbox = document.getElementById("userNameBox");
     // remove anything that may be there for another protocol
     while (vbox.hasChildNodes()) {
       vbox.lastChild.remove();
     }
 
-    var splits = [];
-    for (let split of this.getProtoUserSplits()) {
-      splits.push(split);
-    }
+    var splits = this.proto.getUsernameSplit();
 
     var label = bundle.getString("accountUsername");
     this.userNameBoxes = [this.insertUsernameField("name", label, vbox)];
     this.userNameBoxes[0].emptyText = emptyText;
 
     for (let i = 0; i < splits.length; ++i) {
       this.userNameBoxes.push({ value: splits[i].separator });
       label = bundle.getFormattedString("accountColon", [splits[i].label]);
@@ -219,17 +216,17 @@ var accountWizard = {
 
     let alias = document.getElementById("alias");
     alias.focus();
   },
 
   populateProtoSpecificBox() {
     let haveOptions = accountOptionsHelper.addOptions(
       this.proto.id + "-",
-      this.getProtoOptions()
+      this.proto.getOptions()
     );
     document.getElementById("protoSpecificGroupbox").hidden = !haveOptions;
     if (haveOptions) {
       var bundle = document.getElementById("accountsBundle");
       document.getElementById(
         "protoSpecificCaption"
       ).textContent = bundle.getFormattedString("protoOptions", [
         this.proto.name,
@@ -296,17 +293,17 @@ var accountWizard = {
     /* FIXME
     if (this.proto.newMailNotification)
       rows.appendChild(this.createSummaryRow("Notify of new mails:",
                                              this.getValue("newMailNotification")));
     */
 
     var id = this.proto.id;
     this.prefs = [];
-    for (let opt of this.getProtoOptions()) {
+    for (let opt of this.proto.getOptions()) {
       let name = opt.name;
       let eltName = id + "-" + name;
       let val = this.getValue(eltName);
       // The value will be undefined if the proto specific groupbox has never been opened
       if (val === undefined) {
         continue;
       }
       switch (opt.type) {
@@ -430,22 +427,16 @@ var accountWizard = {
     return undefined;
   },
 
   *getIter(aEnumerator) {
     for (let iter of aEnumerator) {
       yield iter;
     }
   },
-  getProtoOptions() {
-    return this.getIter(this.proto.getOptions());
-  },
-  getProtoUserSplits() {
-    return this.getIter(this.proto.getUsernameSplit());
-  },
 
   /* Check for correctness and set URL for the "Get more protocols..."-link
    *  Stripped down code from preferences/themes.js
    */
   setGetMoreProtocols() {
     let prefURL = PREF_EXTENSIONS_GETMOREPROTOCOLSURL;
     var getMore = document.getElementById("getMoreProtocols");
     var showGetMore = false;