--- a/dom/base/nsIFrameLoader.idl
+++ b/dom/base/nsIFrameLoader.idl
@@ -1,16 +1,15 @@
 /* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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"
 
-interface mozIApplication;
 interface nsFrameLoader;
 interface nsIDocShell;
 interface nsIURI;
 interface nsIFrame;
 interface nsSubDocumentFrame;
 interface nsIMessageSender;
 interface nsIVariant;
 interface nsIDOMElement;
@@ -210,32 +209,26 @@ interface nsIFrameLoader : nsISupports
 };
 
 %{C++
 class nsFrameLoader;
 %}
 
 native alreadyAddRefed_nsFrameLoader(already_AddRefed<nsFrameLoader>);
 
-[scriptable, uuid(adc1b3ba-8deb-4943-8045-e6de0044f2ce)]
+[scriptable, uuid(c4abebcf-55f3-47d4-af15-151311971255)]
 interface nsIFrameLoaderOwner : nsISupports
 {
   /**
    * The frame loader owned by this nsIFrameLoaderOwner
    */
   readonly attribute nsIFrameLoader frameLoader;
   [noscript, notxpcom] alreadyAddRefed_nsFrameLoader GetFrameLoader();
 
   /**
-   * The principal of parent mozIApplication in case of nested mozbrowser
-   * iframes.
-   */
-  readonly attribute mozIApplication parentApplication;
-
-  /**
    * Puts the FrameLoaderOwner in prerendering mode.
    */
   void setIsPrerendered();
 
   /**
    * Swap frame loaders with the given nsIFrameLoaderOwner.  This may
    * only be posible in a very limited range of circumstances, or
    * never, depending on the object implementing this interface.

--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -1211,27 +1211,16 @@ nsObjectLoadingContent::GetFrameLoader(n
 NS_IMETHODIMP_(already_AddRefed<nsFrameLoader>)
 nsObjectLoadingContent::GetFrameLoader()
 {
   RefPtr<nsFrameLoader> loader = mFrameLoader;
   return loader.forget();
 }
 
 NS_IMETHODIMP
-nsObjectLoadingContent::GetParentApplication(mozIApplication** aApplication)
-{
-  if (!aApplication) {
-    return NS_ERROR_FAILURE;
-  }
-
-  *aApplication = nullptr;
-  return NS_OK;
-}
-
-NS_IMETHODIMP
 nsObjectLoadingContent::SetIsPrerendered()
 {
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
 NS_IMETHODIMP
 nsObjectLoadingContent::SwapFrameLoaders(nsIFrameLoaderOwner* aOtherLoader)
 {

--- a/dom/browser-element/BrowserElementAudioChannel.cpp
+++ b/dom/browser-element/BrowserElementAudioChannel.cpp
@@ -2,34 +2,42 @@
  * 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 "BrowserElementAudioChannel.h"
 
 #include "mozilla/Services.h"
 #include "mozilla/dom/BrowserElementAudioChannelBinding.h"
 #include "mozilla/dom/DOMRequest.h"
-#include "mozilla/dom/Element.h"
-#include "mozilla/dom/TabParent.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/PromiseNativeHandler.h"
 #include "mozilla/dom/ToJSValue.h"
 #include "AudioChannelService.h"
 #include "nsIBrowserElementAPI.h"
 #include "nsIDocShell.h"
 #include "nsIDOMDocument.h"
 #include "nsIDOMDOMRequest.h"
 #include "nsIObserverService.h"
 #include "nsISupportsPrimitives.h"
 #include "nsISystemMessagesInternal.h"
 #include "nsITabParent.h"
 #include "nsNetUtil.h"
 #include "nsPIDOMWindow.h"
 #include "nsServiceManagerUtils.h"
 
+namespace {
+
+void
+AssertIsInMainProcess()
+{
+  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
+}
+
+} // anonymous namespace
+
 namespace mozilla {
 namespace dom {
 
 NS_IMPL_ADDREF_INHERITED(BrowserElementAudioChannel, DOMEventTargetHelper)
 NS_IMPL_RELEASE_INHERITED(BrowserElementAudioChannel, DOMEventTargetHelper)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(BrowserElementAudioChannel)
   NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
@@ -76,16 +84,17 @@ BrowserElementAudioChannel::BrowserEleme
   : DOMEventTargetHelper(aWindow)
   , mFrameLoader(aFrameLoader)
   , mBrowserElementAPI(aAPI)
   , mAudioChannel(aAudioChannel)
   , mManifestURL(aManifestURL)
   , mState(eStateUnknown)
 {
   MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
 
   nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
   if (obs) {
     nsAutoString name;
     AudioChannelService::GetAudioChannelString(aAudioChannel, name);
 
     nsAutoCString topic;
     topic.Assign("audiochannel-activity-");
@@ -93,16 +102,17 @@ BrowserElementAudioChannel::BrowserEleme
 
     obs->AddObserver(this, topic.get(), true);
   }
 }
 
 BrowserElementAudioChannel::~BrowserElementAudioChannel()
 {
   MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
 
   nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
   if (obs) {
     nsAutoString name;
     AudioChannelService::GetAudioChannelString(mAudioChannel, name);
 
     nsAutoCString topic;
     topic.Assign("audiochannel-activity-");
@@ -158,16 +168,18 @@ BrowserElementAudioChannel::WrapObject(J
 {
   return BrowserElementAudioChannelBinding::Wrap(aCx, this, aGivenProto);
 }
 
 AudioChannel
 BrowserElementAudioChannel::Name() const
 {
   MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
+
   return mAudioChannel;
 }
 
 namespace {
 
 class BaseRunnable : public nsRunnable
 {
 protected:
@@ -344,16 +356,17 @@ RespondSuccessHandler::RejectedCallback(
 }
 
 } // anonymous namespace
 
 already_AddRefed<dom::DOMRequest>
 BrowserElementAudioChannel::GetVolume(ErrorResult& aRv)
 {
   MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
 
   if (!mFrameWindow) {
     nsCOMPtr<nsIDOMDOMRequest> request;
     aRv = mBrowserElementAPI->GetAudioChannelVolume((uint32_t)mAudioChannel,
                                                     getter_AddRefs(request));
     if (NS_WARN_IF(aRv.Failed())) {
       return nullptr;
     }
@@ -369,16 +382,17 @@ BrowserElementAudioChannel::GetVolume(Er
 
   return domRequest.forget();
 }
 
 already_AddRefed<dom::DOMRequest>
 BrowserElementAudioChannel::SetVolume(float aVolume, ErrorResult& aRv)
 {
   MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
 
   if (!mFrameWindow) {
     nsCOMPtr<nsIDOMDOMRequest> request;
     aRv = mBrowserElementAPI->SetAudioChannelVolume((uint32_t)mAudioChannel,
                                                     aVolume,
                                                     getter_AddRefs(request));
     if (NS_WARN_IF(aRv.Failed())) {
       return nullptr;
@@ -401,16 +415,17 @@ BrowserElementAudioChannel::SetVolume(fl
 
   return domRequest.forget();
 }
 
 already_AddRefed<dom::DOMRequest>
 BrowserElementAudioChannel::GetMuted(ErrorResult& aRv)
 {
   MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
 
   if (!mFrameWindow) {
     nsCOMPtr<nsIDOMDOMRequest> request;
     aRv = mBrowserElementAPI->GetAudioChannelMuted((uint32_t)mAudioChannel,
                                                    getter_AddRefs(request));
     if (NS_WARN_IF(aRv.Failed())) {
       return nullptr;
     }
@@ -426,16 +441,17 @@ BrowserElementAudioChannel::GetMuted(Err
 
   return domRequest.forget();
 }
 
 already_AddRefed<dom::DOMRequest>
 BrowserElementAudioChannel::SetMuted(bool aMuted, ErrorResult& aRv)
 {
   MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
 
   if (!mFrameWindow) {
     nsCOMPtr<nsIDOMDOMRequest> request;
     aRv = mBrowserElementAPI->SetAudioChannelMuted((uint32_t)mAudioChannel,
                                                    aMuted,
                                                    getter_AddRefs(request));
     if (NS_WARN_IF(aRv.Failed())) {
       return nullptr;
@@ -458,16 +474,17 @@ BrowserElementAudioChannel::SetMuted(boo
 
   return domRequest.forget();
 }
 
 already_AddRefed<dom::DOMRequest>
 BrowserElementAudioChannel::IsActive(ErrorResult& aRv)
 {
   MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
 
   if (mState != eStateUnknown) {
     RefPtr<DOMRequest> domRequest = new DOMRequest(GetOwner());
 
     nsCOMPtr<nsIRunnable> runnable =
       new IsActiveRunnable(GetOwner(), mFrameWindow, domRequest, mAudioChannel,
                            mState == eStateActive);
     NS_DispatchToMainThread(runnable);
@@ -571,39 +588,18 @@ BrowserElementAudioChannel::Observe(nsIS
     if (mTabParent == aSubject) {
       ProcessStateChanged(aData);
     }
 
     return NS_OK;
   }
 
   nsCOMPtr<nsISupportsPRUint64> wrapper = do_QueryInterface(aSubject);
-  // This can be a nested iframe.
-  if (!wrapper) {
-    nsCOMPtr<nsITabParent> iTabParent = do_QueryInterface(aSubject);
-    if (!iTabParent) {
-      return NS_ERROR_FAILURE;
-    }
-
-    RefPtr<TabParent> tabParent = TabParent::GetFrom(iTabParent);
-    if (!tabParent) {
-      return NS_ERROR_FAILURE;
-    }
-
-    Element* element = tabParent->GetOwnerElement();
-    if (!element) {
-      return NS_ERROR_FAILURE;
-    }
-
-    nsCOMPtr<nsPIDOMWindow> window = element->OwnerDoc()->GetWindow();
-    if (window == mFrameWindow) {
-      ProcessStateChanged(aData);
-    }
-
-    return NS_OK;
+  if (NS_WARN_IF(!wrapper)) {
+    return NS_ERROR_FAILURE;
   }
 
   uint64_t windowID;
   nsresult rv = wrapper->GetData(&windowID);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 

deleted file mode 100644
--- a/dom/browser-element/mochitest/browserElement_AudioChannel_nested.js
+++ /dev/null
@@ -1,76 +0,0 @@
-/* Any copyright is dedicated to the public domain.
-   http://creativecommons.org/publicdomain/zero/1.0/ */
-
-// Bug 1113086 - tests for AudioChannel API into BrowserElement
-
-"use strict";
-
-SimpleTest.waitForExplicitFinish();
-browserElementTestHelpers.setEnabledPref(true);
-browserElementTestHelpers.addPermission();
-
-function runTests() {
-  var iframe = document.createElement('iframe');
-  iframe.setAttribute('mozbrowser', 'true');
-  iframe.setAttribute('mozapp', 'http://example.org/manifest.webapp');
-
-  var listener = function(e) {
-    var message = e.detail.message;
-    if (/^OK/.exec(message)) {
-      ok(true, "Message from app: " + message);
-    } else if (/^KO/.exec(message)) {
-      ok(false, "Message from app: " + message);
-    } else if (/DONE/.exec(message)) {
-      ok(true, "Messaging from app complete");
-      iframe.removeEventListener('mozbrowsershowmodalprompt', listener);
-    }
-  }
-
-  function audio_loadend() {
-    ok("mute" in iframe, "iframe.mute exists");
-    ok("unmute" in iframe, "iframe.unmute exists");
-    ok("getMuted" in iframe, "iframe.getMuted exists");
-    ok("getVolume" in iframe, "iframe.getVolume exists");
-    ok("setVolume" in iframe, "iframe.setVolume exists");
-
-    ok("allowedAudioChannels" in iframe, "allowedAudioChannels exist");
-    var channels = iframe.allowedAudioChannels;
-    is(channels.length, 1, "1 audio channel by default");
-
-    var ac = channels[0];
-
-    ok(ac instanceof BrowserElementAudioChannel, "Correct class");
-    ok("getVolume" in ac, "ac.getVolume exists");
-    ok("setVolume" in ac, "ac.setVolume exists");
-    ok("getMuted" in ac, "ac.getMuted exists");
-    ok("setMuted" in ac, "ac.setMuted exists");
-    ok("isActive" in ac, "ac.isActive exists");
-
-    info("Setting the volume...");
-    ac.setVolume(0.5);
-
-    ac.onactivestatechanged = function() {
-      ok(true, "activestatechanged event received.");
-      ac.onactivestatechanged = null;
-      SimpleTest.finish();
-    }
-  }
-
-  iframe.addEventListener('mozbrowserloadend', audio_loadend);
-  iframe.addEventListener('mozbrowsershowmodalprompt', listener, false);
-  document.body.appendChild(iframe);
-
-  var context = { 'url': 'http://example.org',
-                  'appId': SpecialPowers.Ci.nsIScriptSecurityManager.NO_APP_ID,
-                  'isInBrowserElement': true };
-  SpecialPowers.pushPermissions([
-    {'type': 'browser', 'allow': 1, 'context': context},
-    {'type': 'embed-apps', 'allow': 1, 'context': context}
-  ], function() {
-    iframe.src = 'http://example.org/tests/dom/browser-element/mochitest/file_browserElement_AudioChannel_nested.html';
-  });
-}
-
-addEventListener('testready', function() {
-  SimpleTest.executeSoon(runTests);
-});

deleted file mode 100644
--- a/dom/browser-element/mochitest/file_browserElement_AudioChannel_nested.html
+++ /dev/null
@@ -1,63 +0,0 @@
-<html>
-<head>
-<script type="text/javascript">
-
-  function ok(a, msg) {
-    alert((!!a ? "OK" : "KO") + " " + msg);
-  }
-
-  function is(a, b, msg) {
-    ok(a === b, msg);
-  }
-
-  function finish(a, b, msg) {
-    alert("DONE");
-  }
-
-  addEventListener('load', function(e) {
-    var iframe = document.createElement('iframe');
-    iframe.setAttribute('mozbrowser', 'true');
-    // set 'remote' to true here will make the the iframe remote in _inproc_
-    // test and in-process in _oop_  test.
-    iframe.setAttribute('remote', 'true');
-    iframe.setAttribute('mozapp', 'http://example.org/manifest.webapp');
-
-    iframe.addEventListener('mozbrowserloadend', function(e) {
-      ok("mute" in iframe, "iframe.mute exists");
-      ok("unmute" in iframe, "iframe.unmute exists");
-      ok("getMuted" in iframe, "iframe.getMuted exists");
-      ok("getVolume" in iframe, "iframe.getVolume exists");
-      ok("setVolume" in iframe, "iframe.setVolume exists");
-
-      ok("allowedAudioChannels" in iframe, "allowedAudioChannels exist");
-      var channels = iframe.allowedAudioChannels;
-      is(channels.length, 1, "1 audio channel by default");
-
-      var ac = channels[0];
-
-      ok(ac instanceof BrowserElementAudioChannel, "Correct class");
-      ok("getVolume" in ac, "ac.getVolume exists");
-      ok("setVolume" in ac, "ac.setVolume exists");
-      ok("getMuted" in ac, "ac.getMuted exists");
-      ok("setMuted" in ac, "ac.setMuted exists");
-      ok("isActive" in ac, "ac.isActive exists");
-
-      ac.onactivestatechanged = function() {
-        ok("activestatechanged event received.");
-
-        ac.getVolume().onsuccess = function(e) {
-          ok(e.target.result, 1, "Default volume is 1");
-        };
-
-        finish();
-      }
-    });
-
-    document.body.appendChild(iframe);
-    iframe.src = 'http://example.org/tests/dom/browser-element/mochitest/file_audio.html';
-  });
-</script>
-</head>
-<body>
-</body>
-</html>

--- a/dom/browser-element/mochitest/mochitest-oop.ini
+++ b/dom/browser-element/mochitest/mochitest-oop.ini
@@ -116,13 +116,12 @@ disabled = bug 930449
 [test_browserElement_oop_CloseFromOpener.html]
 disabled = bug 924771
 [test_browserElement_oop_CloseApp.html]
 disabled = bug 924771
 [test_browserElement_oop_ExposableURI.html]
 disabled = bug 924771
 [test_browserElement_oop_GetContentDimensions.html]
 [test_browserElement_oop_AudioChannel.html]
-[test_browserElement_oop_AudioChannel_nested.html]
 [test_browserElement_oop_SetNFCFocus.html]
 [test_browserElement_oop_getWebManifest.html]
 [test_browserElement_oop_OpenWindowEmpty.html]
 skip-if = (toolkit == 'gonk') # Test doesn't work on B2G emulator

--- a/dom/browser-element/mochitest/mochitest.ini
+++ b/dom/browser-element/mochitest/mochitest.ini
@@ -78,23 +78,21 @@ support-files =
   browserElement_VisibilityChange.js
   browserElement_XFrameOptions.js
   browserElement_XFrameOptionsAllowFrom.js
   browserElement_XFrameOptionsDeny.js
   browserElement_XFrameOptionsSameOrigin.js
   browserElement_XFrameOptionsSameOrigin.js
   browserElement_GetContentDimensions.js
   browserElement_AudioChannel.js
-  browserElement_AudioChannel_nested.js
   file_browserElement_AlertInFrame.html
   file_browserElement_AlertInFrame_Inner.html
   file_browserElement_AllowEmbedAppsInNestedOOIframe.html
   file_browserElement_AppFramePermission.html
   file_browserElement_AppWindowNamespace.html
-  file_browserElement_AudioChannel_nested.html
   file_browserElement_Viewmode.html
   file_browserElement_ThemeColor.html
   file_browserElement_BrowserWindowNamespace.html
   file_browserElement_CloseApp.html
   file_browserElement_CloseFromOpener.html
   file_browserElement_CookiesNotThirdParty.html
   file_browserElement_DisallowEmbedAppsInOOP.html
   file_browserElement_ExecuteScript.html
@@ -247,13 +245,12 @@ skip-if = (toolkit == 'gonk' && !debug)
 [test_browserElement_inproc_XFrameOptionsSameOrigin.html]
 [test_browserElement_oop_NextPaint.html]
 skip-if = (toolkit == 'android' && processor == 'x86') #x86 only bug 936226
 # Disabled due to https://bugzilla.mozilla.org/show_bug.cgi?id=774100
 [test_browserElement_inproc_Reload.html]
 disabled = bug 774100
 [test_browserElement_inproc_GetContentDimensions.html]
 [test_browserElement_inproc_AudioChannel.html]
-[test_browserElement_inproc_AudioChannel_nested.html]
 [test_browserElement_inproc_SetNFCFocus.html]
 [test_browserElement_inproc_getStructuredData.html]
 [test_browserElement_inproc_OpenWindowEmpty.html]
 skip-if = (toolkit == 'gonk') # Test doesn't work on B2G emulator

deleted file mode 100644
--- a/dom/browser-element/mochitest/test_browserElement_inproc_AudioChannel_nested.html
+++ /dev/null
@@ -1,13 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test of browser element audioChannel in nested mozbrowser iframes.</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>
-<script type="application/javascript;version=1.7" src="browserElement_AudioChannel_nested.js">
-</script>
-</body>
-</html>

deleted file mode 100644
--- a/dom/browser-element/mochitest/test_browserElement_oop_AudioChannel_nested.html
+++ /dev/null
@@ -1,13 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test of browser element audioChannel.</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>
-<script type="application/javascript;version=1.7" src="browserElement_AudioChannel_nested.js">
-</script>
-</body>
-</html>

--- a/dom/html/nsBrowserElement.cpp
+++ b/dom/html/nsBrowserElement.cpp
@@ -558,43 +558,36 @@ nsBrowserElement::GetAllowedAudioChannel
     }
 
     nsAutoString manifestURL;
     aRv = mozBrowserFrame->GetAppManifestURL(manifestURL);
     if (NS_WARN_IF(aRv.Failed())) {
       return;
     }
 
-    nsCOMPtr<mozIApplication> parentApp;
-    aRv = GetParentApplication(getter_AddRefs(parentApp));
-    if (NS_WARN_IF(aRv.Failed())) {
-      return;
-    }
-
     MOZ_LOG(AudioChannelService::GetAudioChannelLog(), LogLevel::Debug,
             ("nsBrowserElement, GetAllowedAudioChannels, this = %p\n", this));
 
     GenerateAllowedAudioChannels(window, frameLoader, mBrowserElementAPI,
-                                 manifestURL, parentApp,
-                                 mBrowserElementAudioChannels, aRv);
+                                 manifestURL, mBrowserElementAudioChannels,
+                                 aRv);
     if (NS_WARN_IF(aRv.Failed())) {
       return;
     }
   }
 
   aAudioChannels.AppendElements(mBrowserElementAudioChannels);
 }
 
 /* static */ void
 nsBrowserElement::GenerateAllowedAudioChannels(
                  nsPIDOMWindow* aWindow,
                  nsIFrameLoader* aFrameLoader,
                  nsIBrowserElementAPI* aAPI,
                  const nsAString& aManifestURL,
-                 mozIApplication* aParentApp,
                  nsTArray<RefPtr<BrowserElementAudioChannel>>& aAudioChannels,
                  ErrorResult& aRv)
 {
   MOZ_ASSERT(aAudioChannels.IsEmpty());
 
   nsCOMPtr<nsIAppsService> appsService =
     do_GetService("@mozilla.org/AppsService;1");
   if (NS_WARN_IF(!appsService)) {
@@ -627,29 +620,16 @@ nsBrowserElement::GenerateAllowedAudioCh
 
     bool allowed;
     nsAutoCString permissionName;
 
     for (uint32_t i = 0; audioChannelTable && audioChannelTable[i].tag; ++i) {
       permissionName.AssignASCII("audio-channel-");
       permissionName.AppendASCII(audioChannelTable[i].tag);
 
-      // In case of nested iframes we want to check if the parent has the
-      // permission to use this AudioChannel.
-      if (aParentApp) {
-        aRv = aParentApp->HasPermission(permissionName.get(), &allowed);
-        if (NS_WARN_IF(aRv.Failed())) {
-          return;
-        }
-
-        if (!allowed) {
-          continue;
-        }
-      }
-
       aRv = app->HasPermission(permissionName.get(), &allowed);
       if (NS_WARN_IF(aRv.Failed())) {
         return;
       }
 
       if (allowed) {
         RefPtr<BrowserElementAudioChannel> ac =
           BrowserElementAudioChannel::Create(aWindow, aFrameLoader, aAPI,

--- a/dom/html/nsBrowserElement.h
+++ b/dom/html/nsBrowserElement.h
@@ -120,24 +120,21 @@ public:
                    ErrorResult& aRv);
 
   // Helper
   static void GenerateAllowedAudioChannels(
                  nsPIDOMWindow* aWindow,
                  nsIFrameLoader* aFrameLoader,
                  nsIBrowserElementAPI* aAPI,
                  const nsAString& aManifestURL,
-                 mozIApplication* aParentApp,
                  nsTArray<RefPtr<dom::BrowserElementAudioChannel>>& aAudioChannels,
                  ErrorResult& aRv);
 
 protected:
   NS_IMETHOD_(already_AddRefed<nsFrameLoader>) GetFrameLoader() = 0;
-  NS_IMETHOD GetParentApplication(mozIApplication** aApplication) = 0;
-
   void InitBrowserElementAPI();
   nsCOMPtr<nsIBrowserElementAPI> mBrowserElementAPI;
   nsTArray<RefPtr<dom::BrowserElementAudioChannel>> mBrowserElementAudioChannels;
 
 private:
   bool IsBrowserElementOrThrow(ErrorResult& aRv);
   bool IsNotWidgetOrThrow(ErrorResult& aRv);
   bool mOwnerIsWidget;

--- a/dom/html/nsGenericHTMLFrameElement.cpp
+++ b/dom/html/nsGenericHTMLFrameElement.cpp
@@ -187,45 +187,16 @@ nsGenericHTMLFrameElement::GetFrameLoade
 NS_IMETHODIMP_(already_AddRefed<nsFrameLoader>)
 nsGenericHTMLFrameElement::GetFrameLoader()
 {
   RefPtr<nsFrameLoader> loader = mFrameLoader;
   return loader.forget();
 }
 
 NS_IMETHODIMP
-nsGenericHTMLFrameElement::GetParentApplication(mozIApplication** aApplication)
-{
-  if (!aApplication) {
-    return NS_ERROR_FAILURE;
-  }
-
-  *aApplication = nullptr;
-
-  uint32_t appId;
-  nsIPrincipal *principal = NodePrincipal();
-  nsresult rv = principal->GetAppId(&appId);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return rv;
-  }
-
-  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-  if (NS_WARN_IF(!appsService)) {
-    return NS_ERROR_FAILURE;
-  }
-
-  rv = appsService->GetAppByLocalId(appId, aApplication);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return rv;
-  }
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
 nsGenericHTMLFrameElement::SwapFrameLoaders(nsIFrameLoaderOwner* aOtherOwner)
 {
   // We don't support this yet
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
 NS_IMETHODIMP
 nsGenericHTMLFrameElement::SetIsPrerendered()

--- a/dom/interfaces/base/nsITabParent.idl
+++ b/dom/interfaces/base/nsITabParent.idl
@@ -1,16 +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/. */
 
 
 #include "domstubs.idl"
 
-[builtinclass, scriptable, uuid(8e49f7b0-1f98-4939-bf91-e9c39cd56434)]
+[scriptable, uuid(7615408c-1fb3-4128-8dd5-a3e2f3fa8842)]
 interface nsITabParent : nsISupports
 {
   void injectTouchEvent(in AString aType,
                         [array, size_is(count)] in uint32_t aIdentifiers,
                         [array, size_is(count)] in int32_t aXs,
                         [array, size_is(count)] in int32_t aYs,
                         [array, size_is(count)] in uint32_t aRxs,
                         [array, size_is(count)] in uint32_t aRys,

--- a/dom/system/gonk/AudioChannelManager.cpp
+++ b/dom/system/gonk/AudioChannelManager.cpp
@@ -208,16 +208,16 @@ AudioChannelManager::GetAllowedAudioChan
 
   nsAutoString manifestURL;
   aRv = appsService->GetManifestURLByLocalId(appId, manifestURL);
   if (NS_WARN_IF(aRv.Failed())) {
     return;
   }
 
   nsBrowserElement::GenerateAllowedAudioChannels(window, nullptr, nullptr,
-                                                 manifestURL, nullptr,
-                                                 aAudioChannels, aRv);
+                                                 manifestURL, aAudioChannels,
+                                                 aRv);
   NS_WARN_IF(aRv.Failed());
 }
 
 } // namespace system
 } // namespace dom
 } // namespace mozilla

--- a/dom/xul/nsXULElement.cpp
+++ b/dom/xul/nsXULElement.cpp
@@ -1612,27 +1612,16 @@ nsXULElement::GetFrameLoader()
     if (!slots)
         return nullptr;
 
     RefPtr<nsFrameLoader> loader = slots->mFrameLoader;
     return loader.forget();
 }
 
 nsresult
-nsXULElement::GetParentApplication(mozIApplication** aApplication)
-{
-    if (!aApplication) {
-        return NS_ERROR_FAILURE;
-    }
-
-    *aApplication = nullptr;
-    return NS_OK;
-}
-
-nsresult
 nsXULElement::SetIsPrerendered()
 {
   return SetAttr(kNameSpaceID_None, nsGkAtoms::prerendered, nullptr,
                  NS_LITERAL_STRING("true"), true);
 }
 
 nsresult
 nsXULElement::SwapFrameLoaders(nsIFrameLoaderOwner* aOtherOwner)

--- a/dom/xul/nsXULElement.h
+++ b/dom/xul/nsXULElement.h
@@ -407,17 +407,16 @@ public:
 
     // nsIDOMXULElement
     NS_DECL_NSIDOMXULELEMENT
 
     virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult) const override;
     virtual mozilla::EventStates IntrinsicState() const override;
 
     nsresult GetFrameLoader(nsIFrameLoader** aFrameLoader);
-    nsresult GetParentApplication(mozIApplication** aApplication);
     nsresult SetIsPrerendered();
     nsresult SwapFrameLoaders(nsIFrameLoaderOwner* aOtherOwner);
 
     virtual void RecompileScriptEventListeners() override;
 
     // This function should ONLY be used by BindToTree implementations.
     // The function exists solely because XUL elements store the binding
     // parent as a member instead of in the slots, as Element does.