diff --git a/dom/base/nsFrameLoader.cpp b/dom/base/nsFrameLoader.cpp
index e6b9aaef0f88..22a9832fa4e5 100644
--- a/dom/base/nsFrameLoader.cpp
+++ b/dom/base/nsFrameLoader.cpp
@@ -3043,10 +3043,10 @@ already_AddRefed<Element> nsFrameLoader::GetOwnerElement() {
   return do_AddRef(mOwnerContent);
 }
 
-void nsFrameLoader::SetRemoteBrowser(nsIRemoteTab* aBrowserParent) {
+void nsFrameLoader::InitializeFromBrowserParent(BrowserParent* aBrowserParent) {
   MOZ_ASSERT(!mBrowserParent);
   mIsRemoteFrame = true;
-  mBrowserParent = BrowserParent::GetFrom(aBrowserParent);
+  mBrowserParent = aBrowserParent;
   mChildID = mBrowserParent ? mBrowserParent->Manager()->ChildID() : 0;
   MaybeUpdatePrimaryBrowserParent(eBrowserParentChanged);
   ReallyLoadFrameScripts();
diff --git a/dom/base/nsFrameLoader.h b/dom/base/nsFrameLoader.h
index 4c22faa71dcf..1dd2c6a95b32 100644
--- a/dom/base/nsFrameLoader.h
+++ b/dom/base/nsFrameLoader.h
@@ -342,7 +342,7 @@ class nsFrameLoader final : public nsStubMutationObserver,
    * this object, which means you can't have called ShowRemoteFrame()
    * or ReallyStartLoading().
    */
-  void SetRemoteBrowser(nsIRemoteTab* aBrowserParent);
+  void InitializeFromBrowserParent(BrowserParent* aBrowserParent);
 
   /**
    * Stashes a detached nsIFrame on the frame loader. We do this when we're
diff --git a/dom/html/nsGenericHTMLFrameElement.cpp b/dom/html/nsGenericHTMLFrameElement.cpp
index bdbe023eabce..0379603b5538 100644
--- a/dom/html/nsGenericHTMLFrameElement.cpp
+++ b/dom/html/nsGenericHTMLFrameElement.cpp
@@ -132,12 +132,26 @@ void nsGenericHTMLFrameElement::EnsureFrameLoader() {
   mFrameLoader = nsFrameLoader::Create(this, mOpenerWindow, mNetworkCreated);
 }
 
-nsresult nsGenericHTMLFrameElement::CreateRemoteFrameLoader(
-    nsIRemoteTab* aBrowserParent) {
+void nsGenericHTMLFrameElement::DisallowCreateFrameLoader() {
+  MOZ_ASSERT(!mFrameLoader);
+  MOZ_ASSERT(!mFrameLoaderCreationDisallowed);
+  mFrameLoaderCreationDisallowed = true;
+}
+
+void nsGenericHTMLFrameElement::AllowCreateFrameLoader() {
+  MOZ_ASSERT(!mFrameLoader);
+  MOZ_ASSERT(mFrameLoaderCreationDisallowed);
+  mFrameLoaderCreationDisallowed = false;
+}
+
+void nsGenericHTMLFrameElement::CreateRemoteFrameLoader(
+    BrowserParent* aBrowserParent) {
   MOZ_ASSERT(!mFrameLoader);
   EnsureFrameLoader();
-  NS_ENSURE_STATE(mFrameLoader);
-  mFrameLoader->SetRemoteBrowser(aBrowserParent);
+  if (NS_WARN_IF(!mFrameLoader)) {
+    return;
+  }
+  mFrameLoader->InitializeFromBrowserParent(aBrowserParent);
 
   if (nsSubDocumentFrame* subdocFrame = do_QueryFrame(GetPrimaryFrame())) {
     // The reflow for this element already happened while we were waiting
@@ -146,7 +160,6 @@ nsresult nsGenericHTMLFrameElement::CreateRemoteFrameLoader(
     // ReflowFinished, and we need to do it properly now.
     mFrameLoader->UpdatePositionAndSize(subdocFrame);
   }
-  return NS_OK;
 }
 
 void nsGenericHTMLFrameElement::PresetOpenerWindow(
@@ -442,22 +455,6 @@ NS_IMETHODIMP nsGenericHTMLFrameElement::GetIsolated(bool* aOut) {
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsGenericHTMLFrameElement::DisallowCreateFrameLoader() {
-  MOZ_ASSERT(!mFrameLoader);
-  MOZ_ASSERT(!mFrameLoaderCreationDisallowed);
-  mFrameLoaderCreationDisallowed = true;
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsGenericHTMLFrameElement::AllowCreateFrameLoader() {
-  MOZ_ASSERT(!mFrameLoader);
-  MOZ_ASSERT(mFrameLoaderCreationDisallowed);
-  mFrameLoaderCreationDisallowed = false;
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsGenericHTMLFrameElement::InitializeBrowserAPI() {
   MOZ_ASSERT(mFrameLoader);
diff --git a/dom/html/nsGenericHTMLFrameElement.h b/dom/html/nsGenericHTMLFrameElement.h
index f3badcc4b2b7..a08b615aeef2 100644
--- a/dom/html/nsGenericHTMLFrameElement.h
+++ b/dom/html/nsGenericHTMLFrameElement.h
@@ -19,6 +19,7 @@
 
 namespace mozilla {
 namespace dom {
+class BrowserParent;
 template <typename>
 struct Nullable;
 class WindowProxyHolder;
@@ -90,6 +91,31 @@ class nsGenericHTMLFrameElement : public nsGenericHTMLElement,
                               mozilla::dom::WindowProxyHolder>& aOpenerWindow,
                           mozilla::ErrorResult& aRv);
 
+  /**
+   * Normally, a frame tries to create its frame loader when its src is
+   * modified, or its contentWindow is accessed.
+   *
+   * disallowCreateFrameLoader prevents the frame element from creating its
+   * frame loader (in the same way that not being inside a document prevents the
+   * creation of a frame loader).  allowCreateFrameLoader lifts this
+   * restriction.
+   *
+   * These methods are not re-entrant -- it is an error to call
+   * disallowCreateFrameLoader twice without first calling allowFrameLoader.
+   *
+   * It's also an error to call either method if we already have a frame loader.
+   */
+  void DisallowCreateFrameLoader();
+  void AllowCreateFrameLoader();
+
+  /**
+   * Create a remote (i.e., out-of-process) frame loader attached to the given
+   * remote tab.
+   *
+   * It is an error to call this method if we already have a frame loader.
+   */
+  void CreateRemoteFrameLoader(mozilla::dom::BrowserParent* aBrowserParent);
+
   static void InitStatics();
   static bool BrowserFramesEnabled();
 
diff --git a/dom/interfaces/html/nsIMozBrowserFrame.idl b/dom/interfaces/html/nsIMozBrowserFrame.idl
index 651664b60e89..82449c059f19 100644
--- a/dom/interfaces/html/nsIMozBrowserFrame.idl
+++ b/dom/interfaces/html/nsIMozBrowserFrame.idl
@@ -35,30 +35,6 @@ interface nsIMozBrowserFrame : nsIDOMMozBrowserFrame
    */
   [infallible] readonly attribute boolean isolated;
 
-  /**
-   * Normally, a frame tries to create its frame loader when its src is
-   * modified, or its contentWindow is accessed.
-   *
-   * disallowCreateFrameLoader prevents the frame element from creating its
-   * frame loader (in the same way that not being inside a document prevents the
-   * creation of a frame loader).  allowCreateFrameLoader lifts this restriction.
-   *
-   * These methods are not re-entrant -- it is an error to call
-   * disallowCreateFrameLoader twice without first calling allowFrameLoader.
-   *
-   * It's also an error to call either method if we already have a frame loader.
-   */
-  void disallowCreateFrameLoader();
-  void allowCreateFrameLoader();
-
-  /**
-   * Create a remote (i.e., out-of-process) frame loader attached to the given
-   * remote tab.
-   *
-   * It is an error to call this method if we already have a frame loader.
-   */
-  void createRemoteFrameLoader(in nsIRemoteTab aRemoteTab);
-
   /**
    * Initialize the API, and add frame message listener that supports API
    * invocations.