--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -79,16 +79,18 @@ XPCOMUtils.defineLazyModuleGetters(this,
   ZoomUI: "resource:///modules/ZoomUI.jsm",
 });
 
 if (AppConstants.MOZ_CRASHREPORTER) {
   ChromeUtils.defineModuleGetter(this, "PluginCrashReporter",
     "resource:///modules/ContentCrashHandlers.jsm");
 }
 
+XPCOMUtils.defineLazyScriptGetter(this, "_gBrowser",
+                                  "chrome://browser/content/tabbrowser.js");
 XPCOMUtils.defineLazyScriptGetter(this, "PlacesTreeView",
                                   "chrome://browser/content/places/treeView.js");
 XPCOMUtils.defineLazyScriptGetter(this, ["PlacesInsertionPoint", "PlacesController",
                                          "PlacesControllerDragHelper"],
                                   "chrome://browser/content/places/controller.js");
 XPCOMUtils.defineLazyScriptGetter(this, "PrintUtils",
                                   "chrome://global/content/printUtils.js");
 XPCOMUtils.defineLazyScriptGetter(this, "ZoomManager",

--- a/browser/base/content/browser.xul
+++ b/browser/base/content/browser.xul
@@ -83,17 +83,16 @@
 #include global-scripts.inc
 
 <script type="application/javascript"
 #ifdef BROWSER_XHTML
 xmlns="http://www.w3.org/1999/xhtml"
 #endif
 >
   Services.scriptloader.loadSubScript("chrome://global/content/contentAreaUtils.js", this);
-  Services.scriptloader.loadSubScript("chrome://browser/content/tabbrowser.js", this);
   Services.scriptloader.loadSubScript("chrome://browser/content/search/searchbar.js", this);
 
   window.onload = gBrowserInit.onLoad.bind(gBrowserInit);
   window.onunload = gBrowserInit.onUnload.bind(gBrowserInit);
   window.onclose = WindowIsClosing;
 
 #ifdef BROWSER_XHTML
   window.addEventListener("readystatechange", () => {