diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 26b5c1e4b67e..f4d8843e2df6 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -8743,9 +8743,7 @@ bool nsDocShell::IsSameDocumentNavigation(nsDocShellLoadState* aLoadState,
 }
 
 nsresult nsDocShell::HandleSameDocumentNavigation(
-    nsDocShellLoadState* aLoadState, SameDocumentNavigationState& aState,
-    bool& aSameDocument) {
-  aSameDocument = true;
+    nsDocShellLoadState* aLoadState, SameDocumentNavigationState& aState) {
 #ifdef DEBUG
   SameDocumentNavigationState state;
   MOZ_ASSERT(IsSameDocumentNavigation(aLoadState, state));
@@ -8770,37 +8768,6 @@ nsresult nsDocShell::HandleSameDocumentNavigation(
             ("Upgraded URI to %s", newURI->GetSpecOrDefault().get()));
   }
 
-  // check if aLoadState->URI(), principalURI, mCurrentURI are same origin
-  // skip handling otherwise
-  nsCOMPtr<nsIPrincipal> origPrincipal = doc->NodePrincipal();
-  nsCOMPtr<nsIURI> principalURI = origPrincipal->GetURI();
-  if (origPrincipal->GetIsNullPrincipal()) {
-    nsCOMPtr<nsIPrincipal> precursor = origPrincipal->GetPrecursorPrincipal();
-    if (precursor) {
-      principalURI = precursor->GetURI();
-    }
-
-    auto isLoadableViaInternet = [](nsIURI* uri) {
-      return (uri && (net::SchemeIsHTTP(uri) || net::SchemeIsHTTPS(uri)));
-    };
-
-    if (isLoadableViaInternet(principalURI) &&
-        isLoadableViaInternet(mCurrentURI) && isLoadableViaInternet(newURI)) {
-      nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
-      if (!NS_SUCCEEDED(
-              ssm->CheckSameOriginURI(newURI, principalURI, false, false)) ||
-          !NS_SUCCEEDED(ssm->CheckSameOriginURI(mCurrentURI, principalURI,
-                                                false, false))) {
-        MOZ_LOG(gSHLog, LogLevel::Debug,
-                ("nsDocShell[%p]: possible violation of the same origin policy "
-                 "during same document navigation",
-                 this));
-        aSameDocument = false;
-        return NS_OK;
-      }
-    }
-  }
-
 #ifdef DEBUG
   if (aState.mSameExceptHashes) {
     bool sameExceptHashes = false;
@@ -9397,15 +9364,13 @@ nsresult nsDocShell::InternalLoad(nsDocShellLoadState* aLoadState,
   // document. If the process fails, or if we successfully navigate within the
   // same document, return.
   if (sameDocument) {
-    nsresult rv = HandleSameDocumentNavigation(
-        aLoadState, sameDocumentNavigationState, sameDocument);
+    nsresult rv =
+        HandleSameDocumentNavigation(aLoadState, sameDocumentNavigationState);
     NS_ENSURE_SUCCESS(rv, rv);
     if (shouldTakeFocus) {
       mBrowsingContext->Focus(CallerType::System, IgnoreErrors());
     }
-    if (sameDocument) {
-      return rv;
-    }
+    return rv;
   }
 
   // mContentViewer->PermitUnload can destroy |this| docShell, which
diff --git a/docshell/base/nsDocShell.h b/docshell/base/nsDocShell.h
index b8a3b4b2f4e1..237cf8dc1a54 100644
--- a/docshell/base/nsDocShell.h
+++ b/docshell/base/nsDocShell.h
@@ -1060,8 +1060,7 @@ class nsDocShell final : public nsDocLoader,
   // continuing with new document navigation.
   MOZ_CAN_RUN_SCRIPT
   nsresult HandleSameDocumentNavigation(nsDocShellLoadState* aLoadState,
-                                        SameDocumentNavigationState& aState,
-                                        bool& aSameDocument);
+                                        SameDocumentNavigationState& aState);
 
   uint32_t GetSameDocumentNavigationFlags(nsIURI* aNewURI);
 
diff --git a/dom/ipc/WindowGlobalParent.cpp b/dom/ipc/WindowGlobalParent.cpp
index dc0afc8ec697..bb2d301d5443 100644
--- a/dom/ipc/WindowGlobalParent.cpp
+++ b/dom/ipc/WindowGlobalParent.cpp
@@ -58,8 +58,6 @@
 #include "nsISharePicker.h"
 #include "nsIURIMutator.h"
 #include "nsIWebProgressListener.h"
-#include "nsScriptSecurityManager.h"
-#include "nsIOService.h"
 
 #include "mozilla/dom/DOMException.h"
 #include "mozilla/dom/DOMExceptionBinding.h"
@@ -92,6 +90,7 @@ WindowGlobalParent::WindowGlobalParent(
     uint64_t aOuterWindowId, FieldValues&& aInit)
     : WindowContext(aBrowsingContext, aInnerWindowId, aOuterWindowId,
                     std::move(aInit)),
+      mIsInitialDocument(false),
       mSandboxFlags(0),
       mDocumentHasLoaded(false),
       mDocumentHasUserInteracted(false),
@@ -118,7 +117,7 @@ already_AddRefed<WindowGlobalParent> WindowGlobalParent::CreateDisconnected(
                              aInit.context().mOuterWindowId, std::move(fields));
   wgp->mDocumentPrincipal = aInit.principal();
   wgp->mDocumentURI = aInit.documentURI();
-  wgp->mIsInitialDocument = Some(aInit.isInitialDocument());
+  wgp->mIsInitialDocument = aInit.isInitialDocument();
   wgp->mBlockAllMixedContent = aInit.blockAllMixedContent();
   wgp->mUpgradeInsecureRequests = aInit.upgradeInsecureRequests();
   wgp->mSandboxFlags = aInit.sandboxFlags();
@@ -381,44 +380,7 @@ mozilla::ipc::IPCResult WindowGlobalParent::RecvInternalLoad(
 
 IPCResult WindowGlobalParent::RecvUpdateDocumentURI(nsIURI* aURI) {
   // XXX(nika): Assert that the URI change was one which makes sense (either
-  // about:blank -> a real URI, or a legal push/popstate URI change):
-  nsAutoCString scheme;
-  if (NS_FAILED(aURI->GetScheme(scheme))) {
-    return IPC_FAIL(this, "Setting DocumentURI without scheme.");
-  }
-
-  nsCOMPtr<nsIIOService> ios = do_GetIOService();
-  if (!ios) {
-    return IPC_FAIL(this, "Cannot get IOService");
-  }
-  nsCOMPtr<nsIProtocolHandler> handler;
-  ios->GetProtocolHandler(scheme.get(), getter_AddRefs(handler));
-  if (!handler) {
-    return IPC_FAIL(this, "Setting DocumentURI with unknown protocol.");
-  }
-
-  auto isLoadableViaInternet = [](nsIURI* uri) {
-    return (uri && (net::SchemeIsHTTP(uri) || net::SchemeIsHTTPS(uri)));
-  };
-
-  if (isLoadableViaInternet(aURI)) {
-    nsCOMPtr<nsIURI> principalURI = mDocumentPrincipal->GetURI();
-    if (mDocumentPrincipal->GetIsNullPrincipal()) {
-      nsCOMPtr<nsIPrincipal> precursor =
-          mDocumentPrincipal->GetPrecursorPrincipal();
-      if (precursor) {
-        principalURI = precursor->GetURI();
-      }
-    }
-
-    if (isLoadableViaInternet(principalURI) &&
-        !nsScriptSecurityManager::SecurityCompareURIs(principalURI, aURI)) {
-      return IPC_FAIL(this,
-                      "Setting DocumentURI with a different Origin than "
-                      "principal URI");
-    }
-  }
-
+  // about:blank -> a real URI, or a legal push/popstate URI change?)
   mDocumentURI = aURI;
   return IPC_OK();
 }
diff --git a/dom/ipc/WindowGlobalParent.h b/dom/ipc/WindowGlobalParent.h
index e0f8091a7837..f908ffac10be 100644
--- a/dom/ipc/WindowGlobalParent.h
+++ b/dom/ipc/WindowGlobalParent.h
@@ -151,9 +151,7 @@ class WindowGlobalParent final : public WindowContext,
 
   void GetContentBlockingLog(nsAString& aLog);
 
-  bool IsInitialDocument() {
-    return mIsInitialDocument.isSome() && mIsInitialDocument.value();
-  }
+  bool IsInitialDocument() { return mIsInitialDocument; }
 
   already_AddRefed<mozilla::dom::Promise> PermitUnload(
       PermitUnloadAction aAction, uint32_t aTimeout, mozilla::ErrorResult& aRv);
@@ -257,12 +255,7 @@ class WindowGlobalParent final : public WindowContext,
   mozilla::ipc::IPCResult RecvUpdateDocumentTitle(const nsString& aTitle);
   mozilla::ipc::IPCResult RecvUpdateHttpsOnlyStatus(uint32_t aHttpsOnlyStatus);
   mozilla::ipc::IPCResult RecvSetIsInitialDocument(bool aIsInitialDocument) {
-    if (aIsInitialDocument && mIsInitialDocument.isSome() &&
-        (mIsInitialDocument.value() != aIsInitialDocument)) {
-      return IPC_FAIL_NO_REASON(this);
-    }
-
-    mIsInitialDocument = Some(aIsInitialDocument);
+    mIsInitialDocument = aIsInitialDocument;
     return IPC_OK();
   }
   mozilla::ipc::IPCResult RecvUpdateDocumentSecurityInfo(
@@ -354,7 +347,7 @@ class WindowGlobalParent final : public WindowContext,
   nsCOMPtr<nsIURI> mDocumentURI;
   Maybe<nsString> mDocumentTitle;
 
-  Maybe<bool> mIsInitialDocument;
+  bool mIsInitialDocument;
 
   // True if this window has a "beforeunload" event listener.
   bool mHasBeforeUnload;