diff --git a/docshell/base/WindowContext.h b/docshell/base/WindowContext.h
index 760967aa3432..f43b2685aadf 100644
--- a/docshell/base/WindowContext.h
+++ b/docshell/base/WindowContext.h
@@ -29,6 +29,7 @@ class WindowContext : public nsISupports, public nsWrapperCache {
   BrowsingContextGroup* Group() const;
   uint64_t Id() const { return InnerWindowId(); }
   uint64_t InnerWindowId() const { return mInnerWindowId; }
+  uint64_t OuterWindowId() const { return GetOuterWindowId(); }
   bool IsDiscarded() const { return mIsDiscarded; }
 
   // Cast this object to it's parent-process canonical form.
diff --git a/dom/ipc/WindowGlobalParent.cpp b/dom/ipc/WindowGlobalParent.cpp
index 44f4e6c107af..19c34b37a229 100644
--- a/dom/ipc/WindowGlobalParent.cpp
+++ b/dom/ipc/WindowGlobalParent.cpp
@@ -53,8 +53,6 @@ WindowGlobalParent::WindowGlobalParent(const WindowGlobalInit& aInit,
     : WindowContext(aInit.browsingContext().get(), aInit.innerWindowId(), {}),
       mDocumentPrincipal(aInit.principal()),
       mDocumentURI(aInit.documentURI()),
-      mInnerWindowId(aInit.innerWindowId()),
-      mOuterWindowId(aInit.outerWindowId()),
       mInProcess(aInProcess),
       mIsInitialDocument(false),
       mHasBeforeUnload(false) {
diff --git a/dom/ipc/WindowGlobalParent.h b/dom/ipc/WindowGlobalParent.h
index 2c67a98af01d..be537ee90d6d 100644
--- a/dom/ipc/WindowGlobalParent.h
+++ b/dom/ipc/WindowGlobalParent.h
@@ -102,10 +102,6 @@ class WindowGlobalParent final : public WindowContext,
 
   const nsString& GetDocumentTitle() const { return mDocumentTitle; }
 
-  // Window IDs for inner/outer windows.
-  uint64_t OuterWindowId() { return mOuterWindowId; }
-  uint64_t InnerWindowId() { return mInnerWindowId; }
-
   uint64_t ContentParentId();
 
   int32_t OsPid();
@@ -196,8 +192,6 @@ class WindowGlobalParent final : public WindowContext,
 
   RefPtr<CanonicalBrowsingContext> mBrowsingContext;
   nsRefPtrHashtable<nsStringHashKey, JSWindowActorParent> mWindowActors;
-  uint64_t mInnerWindowId;
-  uint64_t mOuterWindowId;
   bool mInProcess;
   bool mIsInitialDocument;