--- a/content/base/src/nsGkAtomList.h
+++ b/content/base/src/nsGkAtomList.h
@@ -604,17 +604,16 @@ GK_ATOM(mousethrough, "mousethrough")
 GK_ATOM(mouseup, "mouseup")
 GK_ATOM(mozaudiochannel, "mozaudiochannel")
 GK_ATOM(mozasyncpanzoom, "mozasyncpanzoom")
 GK_ATOM(mozfullscreenchange, "mozfullscreenchange")
 GK_ATOM(mozfullscreenerror, "mozfullscreenerror")
 GK_ATOM(mozpasspointerevents, "mozpasspointerevents")
 GK_ATOM(mozpointerlockchange, "mozpointerlockchange")
 GK_ATOM(mozpointerlockerror, "mozpointerlockerror")
-GK_ATOM(mozprivatebrowsing, "mozprivatebrowsing")
 GK_ATOM(moz_opaque, "moz-opaque")
 GK_ATOM(moz_action_hint, "mozactionhint")
 GK_ATOM(x_moz_errormessage, "x-moz-errormessage")
 GK_ATOM(msthemecompatible, "msthemecompatible")
 GK_ATOM(multicol, "multicol")
 GK_ATOM(multiple, "multiple")
 GK_ATOM(muted, "muted")
 GK_ATOM(name, "name")

--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -846,17 +846,16 @@ nsDocShell::nsDocShell():
     mIsExecutingOnLoadHandler(false),
     mIsPrintingOrPP(false),
     mSavingOldViewer(false),
 #ifdef DEBUG
     mInEnsureScriptEnv(false),
 #endif
     mAffectPrivateSessionLifetime(true),
     mInvisible(false),
-    mHasLoadedNonBlankURI(false),
     mDefaultLoadFlags(nsIRequest::LOAD_NORMAL),
     mFrameType(eFrameTypeRegular),
     mOwnOrContainingAppId(nsIScriptSecurityManager::UNKNOWN_APP_ID),
     mParentCharsetSource(0)
 {
     mHistoryID = ++gDocshellIDCounter;
     if (gDocShellCount++ == 0) {
         NS_ASSERTION(sURIFixup == nullptr,
@@ -1924,20 +1923,16 @@ nsDocShell::SetCurrentURI(nsIURI *aURI, 
     // We don't want to send a location change when we're displaying an error
     // page, and we don't want to change our idea of "current URI" either
     if (mLoadType == LOAD_ERROR_PAGE) {
         return false;
     }
 
     mCurrentURI = NS_TryToMakeImmutable(aURI);
     
-    if (!NS_IsAboutBlank(mCurrentURI)) {
-      mHasLoadedNonBlankURI = true;
-    }
-
     bool isRoot = false;   // Is this the root docshell
     bool isSubFrame = false;  // Is this a subframe navigation?
 
     nsCOMPtr<nsIDocShellTreeItem> root;
 
     GetSameTypeRootTreeItem(getter_AddRefs(root));
     if (root.get() == static_cast<nsIDocShellTreeItem *>(this)) 
     {
@@ -2278,25 +2273,16 @@ nsDocShell::SetPrivateBrowsing(bool aUse
                 obs->PrivateModeChanged(aUsePrivateBrowsing);
             }
         }
     }
     return NS_OK;
 }
 
 NS_IMETHODIMP
-nsDocShell::GetHasLoadedNonBlankURI(bool* aResult)
-{
-    NS_ENSURE_ARG_POINTER(aResult);
-
-    *aResult = mHasLoadedNonBlankURI;
-    return NS_OK;
-}
-
-NS_IMETHODIMP
 nsDocShell::GetUseRemoteTabs(bool* aUseRemoteTabs)
 {
     NS_ENSURE_ARG_POINTER(aUseRemoteTabs);
 
     *aUseRemoteTabs = mUseRemoteTabs;
     return NS_OK;
 }
 

--- a/docshell/base/nsDocShell.h
+++ b/docshell/base/nsDocShell.h
@@ -910,17 +910,16 @@ protected:
     
     // @see nsIDocShellHistory::createdDynamically
     bool                       mDynamicallyCreated;
 #ifdef DEBUG
     bool                       mInEnsureScriptEnv;
 #endif
     bool                       mAffectPrivateSessionLifetime;
     bool                       mInvisible;
-    bool                       mHasLoadedNonBlankURI;
     uint64_t                   mHistoryID;
     uint32_t                   mDefaultLoadFlags;
 
     static nsIURIFixup *sURIFixup;
 
     nsRefPtr<nsDOMNavigationTiming> mTiming;
 
     // Are we a regular frame, a browser frame, or an app frame?

--- a/docshell/base/nsIDocShell.idl
+++ b/docshell/base/nsIDocShell.idl
@@ -49,17 +49,17 @@ interface nsIWebBrowserPrint;
 interface nsIVariant;
 interface nsIPrivacyTransitionObserver;
 interface nsIReflowObserver;
 interface nsIScrollObserver;
 interface nsITabParent;
  
 typedef unsigned long nsLoadFlags;
 
-[scriptable, builtinclass, uuid(23157a63-26fd-44a0-a0f9-fdc64dcc004c)]
+[scriptable, builtinclass, uuid(2b8e4a50-7744-454d-a05b-debead8070fe)]
 interface nsIDocShell : nsIDocShellTreeItem
 {
   /**
    * Loads a given URI.  This will give priority to loading the requested URI
    * in the object implementing	this interface.  If it can't be loaded here
    * however, the URL dispatcher will go through its normal process of content
    * loading.
    *
@@ -1012,16 +1012,9 @@ interface nsIDocShell : nsIDocShellTreeI
    * See the documentation for setOpener and getOpener about why we
    * don't use attribute here instead.
    */
   [noscript,notxpcom,nostdcall] void setOpenedRemote(in nsITabParent aOpenedRemote);
   [noscript,notxpcom,nostdcall] nsITabParent getOpenedRemote();
 
   // URLSearchParams for the window.location is owned by the docShell.
   [noscript,notxpcom] URLSearchParams getURLSearchParams();
-
-  /**
-   * This attribute determines whether a document which is not about:blank has
-   * already be loaded by this docShell.
-   */
-  [infallible] readonly attribute boolean hasLoadedNonBlankURI;
-
 };

--- a/dom/browser-element/BrowserElementChild.js
+++ b/dom/browser-element/BrowserElementChild.js
@@ -51,15 +51,8 @@ if (!('BrowserElementIsPreloaded' in thi
 }
 
 var BrowserElementIsReady = true;
 
 let infos = sendSyncMessage('browser-element-api:call',
                             { 'msg_name': 'hello' })[0];
 docShell.QueryInterface(Ci.nsIDocShellTreeItem).name = infos.name;
 docShell.setFullscreenAllowed(infos.fullscreenAllowed);
-if (infos.isPrivate) {
-  if (!docShell.hasLoadedNonBlankURI) {
-    Cu.reportError("We should not switch to Private Browsing after loading a document.");
-  } else {
-    docShell.QueryInterface(Ci.nsILoadContext).usePrivateBrowsing = true;
-  }
-}

--- a/dom/browser-element/BrowserElementParent.cpp
+++ b/dom/browser-element/BrowserElementParent.cpp
@@ -71,24 +71,16 @@ CreateIframe(Element* aOpenerFrameElemen
                              aName, /* aNotify = */ false);
 
   // Indicate whether the iframe is should be remote.
   popupFrameElement->SetAttr(kNameSpaceID_None, nsGkAtoms::Remote,
                              aRemote ? NS_LITERAL_STRING("true") :
                                        NS_LITERAL_STRING("false"),
                              /* aNotify = */ false);
 
-  // Copy the opener frame's mozprivatebrowsing attribute to the popup frame.
-  nsAutoString mozprivatebrowsing;
-  if (aOpenerFrameElement->GetAttr(kNameSpaceID_None, nsGkAtoms::mozprivatebrowsing,
-                                   mozprivatebrowsing)) {
-    popupFrameElement->SetAttr(kNameSpaceID_None, nsGkAtoms::mozprivatebrowsing,
-                               mozprivatebrowsing, /* aNotify = */ false);
-  }
-
   return popupFrameElement.forget();
 }
 
 bool
 DispatchCustomDOMEvent(Element* aFrameElement, const nsAString& aEventName,
                        JSContext* cx, JS::Handle<JS::Value> aDetailValue,
                        nsEventStatus *aStatus)
 {

--- a/dom/browser-element/BrowserElementParent.jsm
+++ b/dom/browser-element/BrowserElementParent.jsm
@@ -384,18 +384,17 @@ BrowserElementParent.prototype = {
       this._domRequestReady = true;
       this._runPendingAPICall();
     }
 
     return {
       name: this._frameElement.getAttribute('name'),
       fullscreenAllowed:
         this._frameElement.hasAttribute('allowfullscreen') ||
-        this._frameElement.hasAttribute('mozallowfullscreen'),
-      isPrivate: this._frameElement.hasAttribute('mozprivatebrowsing')
+        this._frameElement.hasAttribute('mozallowfullscreen')
     };
   },
 
   _fireCtxMenuEvent: function(data) {
     let detail = data.json;
     let evtName = detail.msg_name;
 
     debug('fireCtxMenuEventFromMsg: ' + evtName + ' ' + detail);

--- a/dom/browser-element/mochitest/browserElementTestHelpers.js
+++ b/dom/browser-element/mochitest/browserElementTestHelpers.js
@@ -298,8 +298,281 @@ addEventListener('unload', function() {
   browserElementTestHelpers.cleanUp();
 });
 
 // Wait for the load event before unlocking the test-ready event.
 browserElementTestHelpers.lockTestReady();
 addEventListener('load', function() {
   SimpleTest.executeSoon(browserElementTestHelpers.unlockTestReady.bind(browserElementTestHelpers));
 });
+
+//////////////////////////////////
+// promise.js from the addon SDK with some modifications to the module
+// boilerplate.
+//////////////////////////////////
+
+;(function(id, factory) { // Module boilerplate :(
+    var globals = this;
+    factory(function require(id) {
+      return globals[id];
+    }, (globals[id] = {}), { uri: document.location.href + '#' + id, id: id });
+}).call(this, 'Promise', function Promise(require, exports, module) {
+
+'use strict';
+
+module.metadata = {
+  "stability": "unstable"
+};
+
+/**
+ * Internal utility: Wraps given `value` into simplified promise, successfully
+ * fulfilled to a given `value`. Note the result is not a complete promise
+ * implementation, as its method `then` does not returns anything.
+ */
+function fulfilled(value) {
+  return { then: function then(fulfill) { fulfill(value); } };
+}
+
+/**
+ * Internal utility: Wraps given input into simplified promise, pre-rejected
+ * with a given `reason`. Note the result is not a complete promise
+ * implementation, as its method `then` does not returns anything.
+ */
+function rejected(reason) {
+  return { then: function then(fulfill, reject) { reject(reason); } };
+}
+
+/**
+ * Internal utility: Returns `true` if given `value` is a promise. Value is
+ * assumed to be a promise if it implements method `then`.
+ */
+function isPromise(value) {
+  return value && typeof(value.then) === 'function';
+}
+
+/**
+ * Creates deferred object containing fresh promise & methods to either resolve
+ * or reject it. The result is an object with the following properties:
+ * - `promise` Eventual value representation implementing CommonJS [Promises/A]
+ *   (http://wiki.commonjs.org/wiki/Promises/A) API.
+ * - `resolve` Single shot function that resolves enclosed `promise` with a
+ *   given `value`.
+ * - `reject` Single shot function that rejects enclosed `promise` with a given
+ *   `reason`.
+ *
+ * An optional `prototype` argument is used as a prototype of the returned
+ * `promise` allowing one to implement additional API. If prototype is not
+ * passed then it falls back to `Object.prototype`.
+ *
+ *  ## Example
+ *
+ *  function fetchURI(uri, type) {
+ *    var deferred = defer();
+ *    var request = new XMLHttpRequest();
+ *    request.open("GET", uri, true);
+ *    request.responseType = type;
+ *    request.onload = function onload() {
+ *      deferred.resolve(request.response);
+ *    }
+ *    request.onerror = function(event) {
+ *     deferred.reject(event);
+ *    }
+ *    request.send();
+ *
+ *    return deferred.promise;
+ *  }
+ */
+function defer(prototype) {
+  // Define FIFO queue of observer pairs. Once promise is resolved & all queued
+  // observers are forwarded to `result` and variable is set to `null`.
+  var observers = [];
+
+  // Promise `result`, which will be assigned a resolution value once promise
+  // is resolved. Note that result will always be assigned promise (or alike)
+  // object to take care of propagation through promise chains. If result is
+  // `null` promise is not resolved yet.
+  var result = null;
+
+  prototype = (prototype || prototype === null) ? prototype : Object.prototype;
+
+  // Create an object implementing promise API.
+  var promise = Object.create(prototype, {
+    then: { value: function then(onFulfill, onError) {
+      var deferred = defer(prototype);
+
+      function resolve(value) {
+        // If `onFulfill` handler is provided resolve `deferred.promise` with
+        // result of invoking it with a resolution value. If handler is not
+        // provided propagate value through.
+        try {
+          deferred.resolve(onFulfill ? onFulfill(value) : value);
+        }
+        // `onFulfill` may throw exception in which case resulting promise
+        // is rejected with thrown exception.
+        catch(error) {
+          if (exports._reportErrors && typeof(console) === 'object')
+            console.error(error);
+          // Note: Following is equivalent of `deferred.reject(error)`,
+          // we use this shortcut to reduce a stack.
+          deferred.resolve(rejected(error));
+        }
+      }
+
+      function reject(reason) {
+        try {
+          if (onError) deferred.resolve(onError(reason));
+          else deferred.resolve(rejected(reason));
+        }
+        catch(error) {
+          if (exports._reportErrors && typeof(console) === 'object')
+            console.error(error)
+          deferred.resolve(rejected(error));
+        }
+      }
+
+      // If enclosed promise (`this.promise`) observers queue is still alive
+      // enqueue a new observer pair into it. Note that this does not
+      // necessary means that promise is pending, it may already be resolved,
+      // but we still have to queue observers to guarantee an order of
+      // propagation.
+      if (observers) {
+        observers.push({ resolve: resolve, reject: reject });
+      }
+      // Otherwise just forward observer pair right to a `result` promise.
+      else {
+        result.then(resolve, reject);
+      }
+
+      return deferred.promise;
+    }}
+  })
+
+  var deferred = {
+    promise: promise,
+    /**
+     * Resolves associated `promise` to a given `value`, unless it's already
+     * resolved or rejected. Note that resolved promise is not necessary a
+     * successfully fulfilled. Promise may be resolved with a promise `value`
+     * in which case `value` promise's fulfillment / rejection will propagate
+     * up to a promise resolved with `value`.
+     */
+    resolve: function resolve(value) {
+      if (!result) {
+        // Store resolution `value` in a `result` as a promise, so that all
+        // the subsequent handlers can be simply forwarded to it. Since
+        // `result` will be a promise all the value / error propagation will
+        // be uniformly taken care of.
+        result = isPromise(value) ? value : fulfilled(value);
+
+        // Forward already registered observers to a `result` promise in the
+        // order they were registered. Note that we intentionally dequeue
+        // observer at a time until queue is exhausted. This makes sure that
+        // handlers registered as side effect of observer forwarding are
+        // queued instead of being invoked immediately, guaranteeing FIFO
+        // order.
+        while (observers.length) {
+          var observer = observers.shift();
+          result.then(observer.resolve, observer.reject);
+        }
+
+        // Once `observers` queue is exhausted we `null`-ify it, so that
+        // new handlers are forwarded straight to the `result`.
+        observers = null;
+      }
+    },
+    /**
+     * Rejects associated `promise` with a given `reason`, unless it's already
+     * resolved / rejected. This is just a (better performing) convenience
+     * shortcut for `deferred.resolve(reject(reason))`.
+     */
+    reject: function reject(reason) {
+      // Note that if promise is resolved that does not necessary means that it
+      // is successfully fulfilled. Resolution value may be a promise in which
+      // case its result propagates. In other words if promise `a` is resolved
+      // with promise `b`, `a` is either fulfilled or rejected depending
+      // on weather `b` is fulfilled or rejected. Here `deferred.promise` is
+      // resolved with a promise pre-rejected with a given `reason`, there for
+      // `deferred.promise` is rejected with a given `reason`. This may feel
+      // little awkward first, but doing it this way greatly simplifies
+      // propagation through promise chains.
+      deferred.resolve(rejected(reason));
+    }
+  };
+
+  return deferred;
+}
+exports.defer = defer;
+
+/**
+ * Returns a promise resolved to a given `value`. Optionally a second
+ * `prototype` argument may be provided to be used as a prototype for the
+ * returned promise.
+ */
+function resolve(value, prototype) {
+  var deferred = defer(prototype);
+  deferred.resolve(value);
+  return deferred.promise;
+}
+exports.resolve = resolve;
+
+/**
+ * Returns a promise rejected with a given `reason`. Optionally a second
+ * `prototype` argument may be provided to be used as a prototype for the
+ * returned promise.
+ */
+function reject(reason, prototype) {
+  var deferred = defer(prototype);
+  deferred.reject(reason);
+  return deferred.promise;
+}
+exports.reject = reject;
+
+var promised = (function() {
+  // Note: Define shortcuts and utility functions here in order to avoid
+  // slower property accesses and unnecessary closure creations on each
+  // call of this popular function.
+
+  var call = Function.call;
+  var concat = Array.prototype.concat;
+
+  // Utility function that does following:
+  // execute([ f, self, args...]) => f.apply(self, args)
+  function execute(args) { return call.apply(call, args) }
+
+  // Utility function that takes promise of `a` array and maybe promise `b`
+  // as arguments and returns promise for `a.concat(b)`.
+  function promisedConcat(promises, unknown) {
+    return promises.then(function(values) {
+      return resolve(unknown).then(function(value) {
+        return values.concat([ value ])
+      });
+    });
+  }
+
+  return function promised(f, prototype) {
+    /**
+    Returns a wrapped `f`, which when called returns a promise that resolves to
+    `f(...)` passing all the given arguments to it, which by the way may be
+    promises. Optionally second `prototype` argument may be provided to be used
+    a prototype for a returned promise.
+
+    ## Example
+
+    var promise = promised(Array)(1, promise(2), promise(3))
+    promise.then(console.log) // => [ 1, 2, 3 ]
+    **/
+
+    return function promised() {
+      // create array of [ f, this, args... ]
+      return concat.apply([ f, this ], arguments).
+        // reduce it via `promisedConcat` to get promised array of fulfillments
+        reduce(promisedConcat, resolve([], prototype)).
+        // finally map that to promise of `f.apply(this, args...)`
+        then(execute);
+    }
+  }
+})();
+exports.promised = promised;
+
+var all = promised(Array);
+exports.all = all;
+
+});

deleted file mode 100644
--- a/dom/browser-element/mochitest/browserElement_PrivateBrowsing.js
+++ /dev/null
@@ -1,46 +0,0 @@
-/* Any copyright is dedicated to the public domain.
-   http://creativecommons.org/publicdomain/zero/1.0/ */
-
-// Test that the mozprivatebrowsing attribute works.
-"use strict";
-
-SimpleTest.waitForExplicitFinish();
-browserElementTestHelpers.setEnabledPref(true);
-browserElementTestHelpers.addPermission();
-
-function createFrame(aIsPrivate) {
-  var iframe = document.createElement("iframe");
-  SpecialPowers.wrap(iframe).mozbrowser = true;
-  if (aIsPrivate) {
-    iframe.setAttribute("mozprivatebrowsing", "true");
-  }
-  return iframe;
-}
-
-function createTest(aIsPrivate, aExpected, aNext) {
-  info("createTest " + aIsPrivate + " " + aExpected);
-  return new Promise((aResolve) => {
-    var iframe = createFrame(aIsPrivate);
-    document.body.appendChild(iframe);
-
-    iframe.addEventListener("mozbrowsershowmodalprompt", function(e) {
-      is(e.detail.message, aExpected, "Checking localstorage");
-      aResolve();
-    });
-
-    iframe.src = "file_browserElement_PrivateBrowsing.html";
-  });
-}
-
-function runTest() {
-  // We first create a iframe in non private browsing mode, set up some
-  // localstorage, reopen it to check that we get the previously set value.
-  // Finally, open it in private browsing mode and check that localstorage
-  // is clear.
-  createTest(false, "EMPTY")
-  .then(() => { return createTest(false, "bar"); })
-  .then(() => { return createTest(true, "EMPTY"); })
-  .then(SimpleTest.finish);
-}
-
-addEventListener("testready", runTest);

deleted file mode 100644
--- a/dom/browser-element/mochitest/file_browserElement_PrivateBrowsing.html
+++ /dev/null
@@ -1,10 +0,0 @@
-<html>
-<body>
-<script>
-
-var initialValue = localStorage.getItem("foo") || "EMPTY";
-localStorage.setItem("foo", "bar");
-alert(initialValue);
-</script>
-</body>
-</html>

--- a/dom/browser-element/mochitest/mochitest-oop.ini
+++ b/dom/browser-element/mochitest/mochitest-oop.ini
@@ -54,17 +54,16 @@ skip-if = (toolkit == 'gonk' && !debug)
 skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_oop_OpenWindowDifferentOrigin.html]
 skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_oop_OpenWindowInFrame.html]
 skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_oop_OpenWindowRejected.html]
 skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_oop_Opensearch.html]
-[test_browserElement_oop_PrivateBrowsing.html]
 [test_browserElement_oop_PromptCheck.html]
 [test_browserElement_oop_PromptConfirm.html]
 [test_browserElement_oop_PurgeHistory.html]
 [test_browserElement_oop_Reload.html]
 [test_browserElement_oop_ReloadPostRequest.html]
 [test_browserElement_oop_RemoveBrowserElement.html]
 [test_browserElement_oop_ScrollEvent.html]
 [test_browserElement_oop_SecurityChange.html]

--- a/dom/browser-element/mochitest/mochitest.ini
+++ b/dom/browser-element/mochitest/mochitest.ini
@@ -38,17 +38,16 @@ support-files =
   browserElement_Metachange.js
   browserElement_NextPaint.js
   browserElement_OpenNamed.js
   browserElement_OpenWindow.js
   browserElement_OpenWindowDifferentOrigin.js
   browserElement_OpenWindowInFrame.js
   browserElement_OpenWindowRejected.js
   browserElement_Opensearch.js
-  browserElement_PrivateBrowsing.js
   browserElement_PromptCheck.js
   browserElement_PromptConfirm.js
   browserElement_PurgeHistory.js
   browserElement_Reload.js
   browserElement_ReloadPostRequest.js
   browserElement_RemoveBrowserElement.js
   browserElement_ScrollEvent.js
   browserElement_SecurityChange.js
@@ -85,17 +84,16 @@ support-files =
   file_browserElement_NextPaint.html
   file_browserElement_Open1.html
   file_browserElement_Open2.html
   file_browserElement_OpenNamed.html
   file_browserElement_OpenNamed2.html
   file_browserElement_OpenWindowDifferentOrigin.html
   file_browserElement_OpenWindowInFrame.html
   file_browserElement_OpenWindowRejected.html
-  file_browserElement_PrivateBrowsing.html
   file_browserElement_SecurityChange.html
   file_browserElement_SetVisibleFrames2_Outer.html
   file_browserElement_SetVisibleFrames_Inner.html
   file_browserElement_SetVisibleFrames_Outer.html
   file_browserElement_TargetBlank.html
   file_browserElement_TargetTop.html
   file_browserElement_XFrameOptions.sjs
   file_browserElement_XFrameOptionsAllowFrom.html
@@ -167,17 +165,16 @@ skip-if = (toolkit == 'gonk' && !debug)
 skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_inproc_OpenWindowDifferentOrigin.html]
 skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_inproc_OpenWindowInFrame.html]
 skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_inproc_OpenWindowRejected.html]
 skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_inproc_Opensearch.html]
-[test_browserElement_inproc_PrivateBrowsing.html]
 [test_browserElement_inproc_PromptCheck.html]
 [test_browserElement_inproc_PromptConfirm.html]
 [test_browserElement_inproc_PurgeHistory.html]
 [test_browserElement_inproc_ReloadPostRequest.html]
 [test_browserElement_inproc_RemoveBrowserElement.html]
 [test_browserElement_inproc_ScrollEvent.html]
 [test_browserElement_inproc_SecurityChange.html]
 skip-if = toolkit == 'android' || (toolkit == 'gonk' && !debug) # android(TIMED_OUT, bug 766586) androidx86(TIMED_OUT, bug 766586)

deleted file mode 100644
--- a/dom/browser-element/mochitest/test_browserElement_inproc_PrivateBrowsing.html
+++ /dev/null
@@ -1,19 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=832700
--->
-<head>
-  <title>Test for Bug 832700</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="application/javascript" src="browserElementTestHelpers.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=832700">Mozilla Bug 832700</a>
-
-<script type="application/javascript;version=1.7" src="browserElement_PrivateBrowsing.js">
-</script>
-
-</body>
-</html>

deleted file mode 100644
--- a/dom/browser-element/mochitest/test_browserElement_oop_PrivateBrowsing.html
+++ /dev/null
@@ -1,19 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=832700
--->
-<head>
-  <title>Test for Bug 832700</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="application/javascript" src="browserElementTestHelpers.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=832700">Mozilla Bug 832700</a>
-
-<script type="application/javascript;version=1.7" src="browserElement_PrivateBrowsing.js">
-</script>
-
-</body>
-</html>