new file mode 100644
--- /dev/null
+++ b/browser/base/content/browser-development-helpers.js
@@ -0,0 +1,48 @@
+/* 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/. */
+
+/**
+ * Extra features for local development. This file isn't loaded in
+ * non-local builds.
+ */
+
+var DevelopmentHelpers = {
+  init() {
+    this.quickRestart = this.quickRestart.bind(this);
+    this.addRestartShortcut();
+  },
+
+  quickRestart() {
+    Services.obs.notifyObservers(null, "startupcache-invalidate");
+
+    let env = Cc["@mozilla.org/process/environment;1"].
+              getService(Components.interfaces.nsIEnvironment);
+    env.set("MOZ_DISABLE_SAFE_MODE_KEY", "1");
+
+    Services.startup.quit(Ci.nsIAppStartup.eAttemptQuit | Ci.nsIAppStartup.eRestart);
+  },
+
+  addRestartShortcut() {
+    let command = document.createElement("command");
+    command.setAttribute("id", "cmd_quickRestart");
+    command.addEventListener("command", this.quickRestart, true);
+    command.setAttribute("oncommand", "void 0;"); // Needed - bug 371900
+    document.getElementById("mainCommandSet").prepend(command);
+
+    let key = document.createElement("key");
+    key.setAttribute("id", "key_quickRestart");
+    key.setAttribute("key", "r");
+    key.setAttribute("modifiers", "accel,alt");
+    key.setAttribute("command", "cmd_quickRestart");
+    key.setAttribute("oncommand", "void 0;"); // Needed - bug 371900
+    document.getElementById("mainKeyset").prepend(key);
+
+    let menuitem = document.createElement("menuitem");
+    menuitem.setAttribute("id", "menu_FileRestartItem");
+    menuitem.setAttribute("key", "key_quickRestart");
+    menuitem.setAttribute("label", "Restart (Developer)");
+    menuitem.addEventListener("command", this.quickRestart, true);
+    document.getElementById("menu_FilePopup").appendChild(menuitem);
+  },
+};

--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1683,16 +1683,19 @@ var gBrowserInit = {
     // initialize the sync UI
     requestIdleCallback(() => {
       gSync.init();
     }, {timeout: 1000 * 5});
 
     if (AppConstants.MOZ_DATA_REPORTING)
       gDataNotificationInfoBar.init();
 
+    if (!AppConstants.MOZILLA_OFFICIAL)
+      DevelopmentHelpers.init();
+
     requestIdleCallback(() => {
       // setup simple gestures support
       gGestureSupport.init(true);
 
       // setup history swipe animation
       gHistorySwipeAnimation.init();
     });
 

--- a/browser/base/content/global-scripts.inc
+++ b/browser/base/content/global-scripts.inc
@@ -18,8 +18,12 @@
 <script type="application/javascript" src="chrome://browser/content/browser-plugins.js"/>
 <script type="application/javascript" src="chrome://browser/content/browser-sidebar.js"/>
 <script type="application/javascript" src="chrome://browser/content/browser-tabsintitlebar.js"/>
 <script type="application/javascript" src="chrome://browser/content/browser-trackingprotection.js"/>
 
 #ifdef MOZ_DATA_REPORTING
 <script type="application/javascript" src="chrome://browser/content/browser-data-submission-info-bar.js"/>
 #endif
+
+#ifndef MOZILLA_OFFICIAL
+<script type="application/javascript" src="chrome://browser/content/browser-development-helpers.js"/>
+#endif

--- a/browser/base/jar.mn
+++ b/browser/base/jar.mn
@@ -64,16 +64,19 @@ browser.jar:
         content/browser/browser.js                    (content/browser.js)
 *       content/browser/browser.xul                   (content/browser.xul)
         content/browser/browser-addons.js             (content/browser-addons.js)
         content/browser/browser-captivePortal.js      (content/browser-captivePortal.js)
         content/browser/browser-ctrlTab.js            (content/browser-ctrlTab.js)
         content/browser/browser-customization.js      (content/browser-customization.js)
         content/browser/browser-data-submission-info-bar.js (content/browser-data-submission-info-bar.js)
         content/browser/browser-compacttheme.js       (content/browser-compacttheme.js)
+#ifndef MOZILLA_OFFICIAL
+        content/browser/browser-development-helpers.js (content/browser-development-helpers.js)
+#endif
         content/browser/browser-feeds.js              (content/browser-feeds.js)
         content/browser/browser-fullScreenAndPointerLock.js  (content/browser-fullScreenAndPointerLock.js)
         content/browser/browser-fullZoom.js           (content/browser-fullZoom.js)
         content/browser/browser-gestureSupport.js     (content/browser-gestureSupport.js)
         content/browser/browser-media.js              (content/browser-media.js)
         content/browser/browser-pageActions.js        (content/browser-pageActions.js)
         content/browser/browser-places.js             (content/browser-places.js)
         content/browser/browser-plugins.js            (content/browser-plugins.js)