Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3069 insertions, 0 deletions

diff --git a/docshell/base/CanonicalBrowsingContext.cpp b/docshell/base/CanonicalBrowsingContext.cpp
new file mode 100644
index 0000000000..b6bedf7ba9
--- /dev/null
+++ b/docshell/base/CanonicalBrowsingContext.cpp
@@ -0,0 +1,3069 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "mozilla/dom/CanonicalBrowsingContext.h"
+
+#include "ErrorList.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/AsyncEventDispatcher.h"
+#include "mozilla/dom/BrowserParent.h"
+#include "mozilla/dom/BrowsingContextBinding.h"
+#include "mozilla/dom/BrowsingContextGroup.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/EventTarget.h"
+#include "mozilla/dom/PBrowserParent.h"
+#include "mozilla/dom/PBackgroundSessionStorageCache.h"
+#include "mozilla/dom/PWindowGlobalParent.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+#include "mozilla/dom/ContentProcessManager.h"
+#include "mozilla/dom/MediaController.h"
+#include "mozilla/dom/MediaControlService.h"
+#include "mozilla/dom/ContentPlaybackController.h"
+#include "mozilla/dom/SessionStorageManager.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#ifdef NS_PRINTING
+#  include "mozilla/layout/RemotePrintJobParent.h"
+#endif
+#include "mozilla/net/DocumentLoadListener.h"
+#include "mozilla/NullPrincipal.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/StaticPrefs_docshell.h"
+#include "mozilla/StaticPrefs_fission.h"
+#include "mozilla/Telemetry.h"
+#include "nsILayoutHistoryState.h"
+#include "nsIPrintSettings.h"
+#include "nsIPrintSettingsService.h"
+#include "nsISupports.h"
+#include "nsIWebNavigation.h"
+#include "mozilla/MozPromiseInlines.h"
+#include "nsDocShell.h"
+#include "nsFrameLoader.h"
+#include "nsFrameLoaderOwner.h"
+#include "nsGlobalWindowOuter.h"
+#include "nsIWebBrowserChrome.h"
+#include "nsIXULRuntime.h"
+#include "nsNetUtil.h"
+#include "nsSHistory.h"
+#include "nsSecureBrowserUI.h"
+#include "nsQueryObject.h"
+#include "nsBrowserStatusFilter.h"
+#include "nsIBrowser.h"
+#include "nsTHashSet.h"
+#include "SessionStoreFunctions.h"
+#include "nsIXPConnect.h"
+#include "nsImportModule.h"
+#include "UnitTransforms.h"
+
+using namespace mozilla::ipc;
+
+extern mozilla::LazyLogModule gAutoplayPermissionLog;
+extern mozilla::LazyLogModule gSHLog;
+extern mozilla::LazyLogModule gSHIPBFCacheLog;
+
+#define AUTOPLAY_LOG(msg, ...) \
+  MOZ_LOG(gAutoplayPermissionLog, LogLevel::Debug, (msg, ##__VA_ARGS__))
+
+static mozilla::LazyLogModule sPBContext("PBContext");
+
+// Global count of canonical browsing contexts with the private attribute set
+static uint32_t gNumberOfPrivateContexts = 0;
+
+// Current parent process epoch for parent initiated navigations
+static uint64_t gParentInitiatedNavigationEpoch = 0;
+
+static void IncreasePrivateCount() {
+  gNumberOfPrivateContexts++;
+  MOZ_LOG(sPBContext, mozilla::LogLevel::Debug,
+          ("%s: Private browsing context count %d -> %d", __func__,
+           gNumberOfPrivateContexts - 1, gNumberOfPrivateContexts));
+  if (gNumberOfPrivateContexts > 1) {
+    return;
+  }
+
+  static bool sHasSeenPrivateContext = false;
+  if (!sHasSeenPrivateContext) {
+    sHasSeenPrivateContext = true;
+    mozilla::Telemetry::ScalarSet(
+        mozilla::Telemetry::ScalarID::DOM_PARENTPROCESS_PRIVATE_WINDOW_USED,
+        true);
+  }
+}
+
+static void DecreasePrivateCount() {
+  MOZ_ASSERT(gNumberOfPrivateContexts > 0);
+  gNumberOfPrivateContexts--;
+
+  MOZ_LOG(sPBContext, mozilla::LogLevel::Debug,
+          ("%s: Private browsing context count %d -> %d", __func__,
+           gNumberOfPrivateContexts + 1, gNumberOfPrivateContexts));
+  if (!gNumberOfPrivateContexts &&
+      !mozilla::StaticPrefs::browser_privatebrowsing_autostart()) {
+    nsCOMPtr<nsIObserverService> observerService =
+        mozilla::services::GetObserverService();
+    if (observerService) {
+      MOZ_LOG(sPBContext, mozilla::LogLevel::Debug,
+              ("%s: last-pb-context-exited fired", __func__));
+      observerService->NotifyObservers(nullptr, "last-pb-context-exited",
+                                       nullptr);
+    }
+  }
+}
+
+namespace mozilla {
+namespace dom {
+
+extern mozilla::LazyLogModule gUserInteractionPRLog;
+
+#define USER_ACTIVATION_LOG(msg, ...) \
+  MOZ_LOG(gUserInteractionPRLog, LogLevel::Debug, (msg, ##__VA_ARGS__))
+
+CanonicalBrowsingContext::CanonicalBrowsingContext(WindowContext* aParentWindow,
+                                                   BrowsingContextGroup* aGroup,
+                                                   uint64_t aBrowsingContextId,
+                                                   uint64_t aOwnerProcessId,
+                                                   uint64_t aEmbedderProcessId,
+                                                   BrowsingContext::Type aType,
+                                                   FieldValues&& aInit)
+    : BrowsingContext(aParentWindow, aGroup, aBrowsingContextId, aType,
+                      std::move(aInit)),
+      mProcessId(aOwnerProcessId),
+      mEmbedderProcessId(aEmbedderProcessId),
+      mPermanentKey(JS::NullValue()) {
+  // You are only ever allowed to create CanonicalBrowsingContexts in the
+  // parent process.
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+
+  // The initial URI in a BrowsingContext is always "about:blank".
+  MOZ_ALWAYS_SUCCEEDS(
+      NS_NewURI(getter_AddRefs(mCurrentRemoteURI), "about:blank"));
+
+  mozilla::HoldJSObjects(this);
+}
+
+CanonicalBrowsingContext::~CanonicalBrowsingContext() {
+  mPermanentKey.setNull();
+
+  mozilla::DropJSObjects(this);
+
+  if (mSessionHistory) {
+    mSessionHistory->SetBrowsingContext(nullptr);
+  }
+}
+
+/* static */
+already_AddRefed<CanonicalBrowsingContext> CanonicalBrowsingContext::Get(
+    uint64_t aId) {
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+  return BrowsingContext::Get(aId).downcast<CanonicalBrowsingContext>();
+}
+
+/* static */
+CanonicalBrowsingContext* CanonicalBrowsingContext::Cast(
+    BrowsingContext* aContext) {
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+  return static_cast<CanonicalBrowsingContext*>(aContext);
+}
+
+/* static */
+const CanonicalBrowsingContext* CanonicalBrowsingContext::Cast(
+    const BrowsingContext* aContext) {
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+  return static_cast<const CanonicalBrowsingContext*>(aContext);
+}
+
+already_AddRefed<CanonicalBrowsingContext> CanonicalBrowsingContext::Cast(
+    already_AddRefed<BrowsingContext>&& aContext) {
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+  return aContext.downcast<CanonicalBrowsingContext>();
+}
+
+ContentParent* CanonicalBrowsingContext::GetContentParent() const {
+  if (mProcessId == 0) {
+    return nullptr;
+  }
+
+  ContentProcessManager* cpm = ContentProcessManager::GetSingleton();
+  if (!cpm) {
+    return nullptr;
+  }
+  return cpm->GetContentProcessById(ContentParentId(mProcessId));
+}
+
+void CanonicalBrowsingContext::GetCurrentRemoteType(nsACString& aRemoteType,
+                                                    ErrorResult& aRv) const {
+  // If we're in the parent process, dump out the void string.
+  if (mProcessId == 0) {
+    aRemoteType = NOT_REMOTE_TYPE;
+    return;
+  }
+
+  ContentParent* cp = GetContentParent();
+  if (!cp) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return;
+  }
+
+  aRemoteType = cp->GetRemoteType();
+}
+
+void CanonicalBrowsingContext::SetOwnerProcessId(uint64_t aProcessId) {
+  MOZ_LOG(GetLog(), LogLevel::Debug,
+          ("SetOwnerProcessId for 0x%08" PRIx64 " (0x%08" PRIx64
+           " -> 0x%08" PRIx64 ")",
+           Id(), mProcessId, aProcessId));
+
+  mProcessId = aProcessId;
+}
+
+nsISecureBrowserUI* CanonicalBrowsingContext::GetSecureBrowserUI() {
+  if (!IsTop()) {
+    return nullptr;
+  }
+  if (!mSecureBrowserUI) {
+    mSecureBrowserUI = new nsSecureBrowserUI(this);
+  }
+  return mSecureBrowserUI;
+}
+
+namespace {
+// The DocShellProgressBridge is attached to a root content docshell loaded in
+// the parent process. Notifications are paired up with the docshell which they
+// came from, so that they can be fired to the correct
+// BrowsingContextWebProgress and bubble through this tree separately.
+//
+// Notifications are filtered by a nsBrowserStatusFilter before being received
+// by the DocShellProgressBridge.
+class DocShellProgressBridge : public nsIWebProgressListener {
+ public:
+  NS_DECL_ISUPPORTS
+  // NOTE: This relies in the expansion of `NS_FORWARD_SAFE` and all listener
+  // methods accepting an `aWebProgress` argument. If this changes in the
+  // future, this may need to be written manually.
+  NS_FORWARD_SAFE_NSIWEBPROGRESSLISTENER(GetTargetContext(aWebProgress))
+
+  explicit DocShellProgressBridge(uint64_t aTopContextId)
+      : mTopContextId(aTopContextId) {}
+
+ private:
+  virtual ~DocShellProgressBridge() = default;
+
+  nsIWebProgressListener* GetTargetContext(nsIWebProgress* aWebProgress) {
+    RefPtr<CanonicalBrowsingContext> context;
+    if (nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(aWebProgress)) {
+      context = docShell->GetBrowsingContext()->Canonical();
+    } else {
+      context = CanonicalBrowsingContext::Get(mTopContextId);
+    }
+    return context && !context->IsDiscarded() ? context->GetWebProgress()
+                                              : nullptr;
+  }
+
+  uint64_t mTopContextId = 0;
+};
+
+NS_IMPL_ISUPPORTS(DocShellProgressBridge, nsIWebProgressListener)
+}  // namespace
+
+void CanonicalBrowsingContext::MaybeAddAsProgressListener(
+    nsIWebProgress* aWebProgress) {
+  // Only add as a listener if the created docshell is a toplevel content
+  // docshell. We'll get notifications for all of our subframes through a single
+  // listener.
+  if (!IsTopContent()) {
+    return;
+  }
+
+  if (!mDocShellProgressBridge) {
+    mDocShellProgressBridge = new DocShellProgressBridge(Id());
+    mStatusFilter = new nsBrowserStatusFilter();
+    mStatusFilter->AddProgressListener(mDocShellProgressBridge,
+                                       nsIWebProgress::NOTIFY_ALL);
+  }
+
+  aWebProgress->AddProgressListener(mStatusFilter, nsIWebProgress::NOTIFY_ALL);
+}
+
+void CanonicalBrowsingContext::ReplacedBy(
+    CanonicalBrowsingContext* aNewContext,
+    const NavigationIsolationOptions& aRemotenessOptions) {
+  MOZ_ASSERT(!aNewContext->mWebProgress);
+  MOZ_ASSERT(!aNewContext->mSessionHistory);
+  MOZ_ASSERT(IsTop() && aNewContext->IsTop());
+
+  mIsReplaced = true;
+  aNewContext->mIsReplaced = false;
+
+  if (mStatusFilter) {
+    mStatusFilter->RemoveProgressListener(mDocShellProgressBridge);
+    mStatusFilter = nullptr;
+  }
+
+  mWebProgress->ContextReplaced(aNewContext);
+  aNewContext->mWebProgress = std::move(mWebProgress);
+
+  // Use the Transaction for the fields which need to be updated whether or not
+  // the new context has been attached before.
+  // SetWithoutSyncing can be used if context hasn't been attached.
+  Transaction txn;
+  txn.SetBrowserId(GetBrowserId());
+  txn.SetIsAppTab(GetIsAppTab());
+  txn.SetHasSiblings(GetHasSiblings());
+  txn.SetHistoryID(GetHistoryID());
+  txn.SetExplicitActive(GetExplicitActive());
+  txn.SetEmbedderColorSchemes(GetEmbedderColorSchemes());
+  txn.SetHasRestoreData(GetHasRestoreData());
+  txn.SetShouldDelayMediaFromStart(GetShouldDelayMediaFromStart());
+
+  // Propagate some settings on BrowsingContext replacement so they're not lost
+  // on bfcached navigations. These are important for GeckoView (see bug
+  // 1781936).
+  txn.SetAllowJavascript(GetAllowJavascript());
+  txn.SetForceEnableTrackingProtection(GetForceEnableTrackingProtection());
+  txn.SetUserAgentOverride(GetUserAgentOverride());
+  txn.SetSuspendMediaWhenInactive(GetSuspendMediaWhenInactive());
+  txn.SetDisplayMode(GetDisplayMode());
+  txn.SetForceDesktopViewport(GetForceDesktopViewport());
+  txn.SetIsUnderHiddenEmbedderElement(GetIsUnderHiddenEmbedderElement());
+
+  // Propagate the default load flags so that the TRR mode flags are forwarded
+  // to the new browsing context. See bug 1828643.
+  txn.SetDefaultLoadFlags(GetDefaultLoadFlags());
+
+  // As this is a different BrowsingContext, set InitialSandboxFlags to the
+  // current flags in the new context so that they also apply to any initial
+  // about:blank documents created in it.
+  txn.SetSandboxFlags(GetSandboxFlags());
+  txn.SetInitialSandboxFlags(GetSandboxFlags());
+  txn.SetTargetTopLevelLinkClicksToBlankInternal(
+      TargetTopLevelLinkClicksToBlank());
+  if (aNewContext->EverAttached()) {
+    MOZ_ALWAYS_SUCCEEDS(txn.Commit(aNewContext));
+  } else {
+    txn.CommitWithoutSyncing(aNewContext);
+  }
+
+  aNewContext->mRestoreState = mRestoreState.forget();
+  MOZ_ALWAYS_SUCCEEDS(SetHasRestoreData(false));
+
+  // XXXBFCache name handling is still a bit broken in Fission in general,
+  // at least in case name should be cleared.
+  if (aRemotenessOptions.mTryUseBFCache) {
+    MOZ_ASSERT(!aNewContext->EverAttached());
+    aNewContext->mFields.SetWithoutSyncing<IDX_Name>(GetName());
+    // We don't copy over HasLoadedNonInitialDocument here, we'll actually end
+    // up loading a new initial document at this point, before the real load.
+    // The real load will then end up setting HasLoadedNonInitialDocument to
+    // true.
+  }
+
+  if (mSessionHistory) {
+    mSessionHistory->SetBrowsingContext(aNewContext);
+    // At this point we will be creating a new ChildSHistory in the child.
+    // That means that the child's epoch will be reset, so it makes sense to
+    // reset the epoch in the parent too.
+    mSessionHistory->SetEpoch(0, Nothing());
+    mSessionHistory.swap(aNewContext->mSessionHistory);
+    RefPtr<ChildSHistory> childSHistory = ForgetChildSHistory();
+    aNewContext->SetChildSHistory(childSHistory);
+  }
+
+  if (mozilla::SessionHistoryInParent()) {
+    BackgroundSessionStorageManager::PropagateManager(Id(), aNewContext->Id());
+  }
+
+  // Transfer the ownership of the priority active status from the old context
+  // to the new context.
+  aNewContext->mPriorityActive = mPriorityActive;
+  mPriorityActive = false;
+
+  MOZ_ASSERT(aNewContext->mLoadingEntries.IsEmpty());
+  mLoadingEntries.SwapElements(aNewContext->mLoadingEntries);
+  MOZ_ASSERT(!aNewContext->mActiveEntry);
+  mActiveEntry.swap(aNewContext->mActiveEntry);
+
+  aNewContext->mPermanentKey = mPermanentKey;
+  mPermanentKey.setNull();
+}
+
+void CanonicalBrowsingContext::UpdateSecurityState() {
+  if (mSecureBrowserUI) {
+    mSecureBrowserUI->RecomputeSecurityFlags();
+  }
+}
+
+void CanonicalBrowsingContext::GetWindowGlobals(
+    nsTArray<RefPtr<WindowGlobalParent>>& aWindows) {
+  aWindows.SetCapacity(GetWindowContexts().Length());
+  for (auto& window : GetWindowContexts()) {
+    aWindows.AppendElement(static_cast<WindowGlobalParent*>(window.get()));
+  }
+}
+
+WindowGlobalParent* CanonicalBrowsingContext::GetCurrentWindowGlobal() const {
+  return static_cast<WindowGlobalParent*>(GetCurrentWindowContext());
+}
+
+WindowGlobalParent* CanonicalBrowsingContext::GetParentWindowContext() {
+  return static_cast<WindowGlobalParent*>(
+      BrowsingContext::GetParentWindowContext());
+}
+
+WindowGlobalParent* CanonicalBrowsingContext::GetTopWindowContext() {
+  return static_cast<WindowGlobalParent*>(
+      BrowsingContext::GetTopWindowContext());
+}
+
+already_AddRefed<nsIWidget>
+CanonicalBrowsingContext::GetParentProcessWidgetContaining() {
+  // If our document is loaded in-process, such as chrome documents, get the
+  // widget directly from our outer window. Otherwise, try to get the widget
+  // from the toplevel content's browser's element.
+  nsCOMPtr<nsIWidget> widget;
+  if (nsGlobalWindowOuter* window = nsGlobalWindowOuter::Cast(GetDOMWindow())) {
+    widget = window->GetNearestWidget();
+  } else if (Element* topEmbedder = Top()->GetEmbedderElement()) {
+    widget = nsContentUtils::WidgetForContent(topEmbedder);
+    if (!widget) {
+      widget = nsContentUtils::WidgetForDocument(topEmbedder->OwnerDoc());
+    }
+  }
+
+  if (widget) {
+    widget = widget->GetTopLevelWidget();
+  }
+
+  return widget.forget();
+}
+
+already_AddRefed<nsIBrowserDOMWindow>
+CanonicalBrowsingContext::GetBrowserDOMWindow() {
+  RefPtr<CanonicalBrowsingContext> chromeTop = TopCrossChromeBoundary();
+  if (nsCOMPtr<nsIDOMChromeWindow> chromeWin =
+          do_QueryInterface(chromeTop->GetDOMWindow())) {
+    nsCOMPtr<nsIBrowserDOMWindow> bdw;
+    if (NS_SUCCEEDED(chromeWin->GetBrowserDOMWindow(getter_AddRefs(bdw)))) {
+      return bdw.forget();
+    }
+  }
+  return nullptr;
+}
+
+already_AddRefed<WindowGlobalParent>
+CanonicalBrowsingContext::GetEmbedderWindowGlobal() const {
+  uint64_t windowId = GetEmbedderInnerWindowId();
+  if (windowId == 0) {
+    return nullptr;
+  }
+
+  return WindowGlobalParent::GetByInnerWindowId(windowId);
+}
+
+already_AddRefed<CanonicalBrowsingContext>
+CanonicalBrowsingContext::GetParentCrossChromeBoundary() {
+  if (GetParent()) {
+    return do_AddRef(Cast(GetParent()));
+  }
+  if (GetEmbedderElement()) {
+    return do_AddRef(
+        Cast(GetEmbedderElement()->OwnerDoc()->GetBrowsingContext()));
+  }
+  return nullptr;
+}
+
+already_AddRefed<CanonicalBrowsingContext>
+CanonicalBrowsingContext::TopCrossChromeBoundary() {
+  RefPtr<CanonicalBrowsingContext> bc(this);
+  while (RefPtr<CanonicalBrowsingContext> parent =
+             bc->GetParentCrossChromeBoundary()) {
+    bc = parent.forget();
+  }
+  return bc.forget();
+}
+
+Nullable<WindowProxyHolder> CanonicalBrowsingContext::GetTopChromeWindow() {
+  RefPtr<CanonicalBrowsingContext> bc = TopCrossChromeBoundary();
+  if (bc->IsChrome()) {
+    return WindowProxyHolder(bc.forget());
+  }
+  return nullptr;
+}
+
+nsISHistory* CanonicalBrowsingContext::GetSessionHistory() {
+  if (!IsTop()) {
+    return Cast(Top())->GetSessionHistory();
+  }
+
+  // Check GetChildSessionHistory() to make sure that this BrowsingContext has
+  // session history enabled.
+  if (!mSessionHistory && GetChildSessionHistory()) {
+    mSessionHistory = new nsSHistory(this);
+  }
+
+  return mSessionHistory;
+}
+
+SessionHistoryEntry* CanonicalBrowsingContext::GetActiveSessionHistoryEntry() {
+  return mActiveEntry;
+}
+
+void CanonicalBrowsingContext::SetActiveSessionHistoryEntry(
+    SessionHistoryEntry* aEntry) {
+  mActiveEntry = aEntry;
+}
+
+bool CanonicalBrowsingContext::HasHistoryEntry(nsISHEntry* aEntry) {
+  // XXX Should we check also loading entries?
+  return aEntry && mActiveEntry == aEntry;
+}
+
+void CanonicalBrowsingContext::SwapHistoryEntries(nsISHEntry* aOldEntry,
+                                                  nsISHEntry* aNewEntry) {
+  // XXX Should we check also loading entries?
+  if (mActiveEntry == aOldEntry) {
+    nsCOMPtr<SessionHistoryEntry> newEntry = do_QueryInterface(aNewEntry);
+    mActiveEntry = newEntry.forget();
+  }
+}
+
+void CanonicalBrowsingContext::AddLoadingSessionHistoryEntry(
+    uint64_t aLoadId, SessionHistoryEntry* aEntry) {
+  Unused << SetHistoryID(aEntry->DocshellID());
+  mLoadingEntries.AppendElement(LoadingSessionHistoryEntry{aLoadId, aEntry});
+}
+
+void CanonicalBrowsingContext::GetLoadingSessionHistoryInfoFromParent(
+    Maybe<LoadingSessionHistoryInfo>& aLoadingInfo) {
+  nsISHistory* shistory = GetSessionHistory();
+  if (!shistory || !GetParent()) {
+    return;
+  }
+
+  SessionHistoryEntry* parentSHE =
+      GetParent()->Canonical()->GetActiveSessionHistoryEntry();
+  if (parentSHE) {
+    int32_t index = -1;
+    for (BrowsingContext* sibling : GetParent()->Children()) {
+      ++index;
+      if (sibling == this) {
+        nsCOMPtr<nsISHEntry> shEntry;
+        parentSHE->GetChildSHEntryIfHasNoDynamicallyAddedChild(
+            index, getter_AddRefs(shEntry));
+        nsCOMPtr<SessionHistoryEntry> she = do_QueryInterface(shEntry);
+        if (she) {
+          aLoadingInfo.emplace(she);
+          mLoadingEntries.AppendElement(LoadingSessionHistoryEntry{
+              aLoadingInfo.value().mLoadId, she.get()});
+          Unused << SetHistoryID(she->DocshellID());
+        }
+        break;
+      }
+    }
+  }
+}
+
+UniquePtr<LoadingSessionHistoryInfo>
+CanonicalBrowsingContext::CreateLoadingSessionHistoryEntryForLoad(
+    nsDocShellLoadState* aLoadState, SessionHistoryEntry* existingEntry,
+    nsIChannel* aChannel) {
+  RefPtr<SessionHistoryEntry> entry;
+  const LoadingSessionHistoryInfo* existingLoadingInfo =
+      aLoadState->GetLoadingSessionHistoryInfo();
+  MOZ_ASSERT_IF(!existingLoadingInfo, !existingEntry);
+  if (existingLoadingInfo) {
+    if (existingEntry) {
+      entry = existingEntry;
+    } else {
+      MOZ_ASSERT(!existingLoadingInfo->mLoadIsFromSessionHistory);
+
+      SessionHistoryEntry::LoadingEntry* loadingEntry =
+          SessionHistoryEntry::GetByLoadId(existingLoadingInfo->mLoadId);
+      MOZ_LOG(gSHLog, LogLevel::Verbose,
+              ("SHEntry::GetByLoadId(%" PRIu64 ") -> %p",
+               existingLoadingInfo->mLoadId, entry.get()));
+      if (!loadingEntry) {
+        return nullptr;
+      }
+      entry = loadingEntry->mEntry;
+    }
+
+    // If the entry was updated, update also the LoadingSessionHistoryInfo.
+    UniquePtr<LoadingSessionHistoryInfo> lshi =
+        MakeUnique<LoadingSessionHistoryInfo>(entry, existingLoadingInfo);
+    aLoadState->SetLoadingSessionHistoryInfo(std::move(lshi));
+    existingLoadingInfo = aLoadState->GetLoadingSessionHistoryInfo();
+    Unused << SetHistoryEntryCount(entry->BCHistoryLength());
+  } else if (aLoadState->LoadType() == LOAD_REFRESH &&
+             !ShouldAddEntryForRefresh(aLoadState->URI(),
+                                       aLoadState->PostDataStream()) &&
+             mActiveEntry) {
+    entry = mActiveEntry;
+  } else {
+    entry = new SessionHistoryEntry(aLoadState, aChannel);
+    if (IsTop()) {
+      // Only top level pages care about Get/SetPersist.
+      entry->SetPersist(
+          nsDocShell::ShouldAddToSessionHistory(aLoadState->URI(), aChannel));
+    } else if (mActiveEntry || !mLoadingEntries.IsEmpty()) {
+      entry->SetIsSubFrame(true);
+    }
+    entry->SetDocshellID(GetHistoryID());
+    entry->SetIsDynamicallyAdded(CreatedDynamically());
+    entry->SetForInitialLoad(true);
+  }
+  MOZ_DIAGNOSTIC_ASSERT(entry);
+
+  UniquePtr<LoadingSessionHistoryInfo> loadingInfo;
+  if (existingLoadingInfo) {
+    loadingInfo = MakeUnique<LoadingSessionHistoryInfo>(*existingLoadingInfo);
+  } else {
+    loadingInfo = MakeUnique<LoadingSessionHistoryInfo>(entry);
+    mLoadingEntries.AppendElement(
+        LoadingSessionHistoryEntry{loadingInfo->mLoadId, entry});
+  }
+
+  MOZ_ASSERT(SessionHistoryEntry::GetByLoadId(loadingInfo->mLoadId)->mEntry ==
+             entry);
+
+  return loadingInfo;
+}
+
+UniquePtr<LoadingSessionHistoryInfo>
+CanonicalBrowsingContext::ReplaceLoadingSessionHistoryEntryForLoad(
+    LoadingSessionHistoryInfo* aInfo, nsIChannel* aNewChannel) {
+  MOZ_ASSERT(aInfo);
+  MOZ_ASSERT(aNewChannel);
+
+  SessionHistoryInfo newInfo = SessionHistoryInfo(
+      aNewChannel, aInfo->mInfo.LoadType(),
+      aInfo->mInfo.GetPartitionedPrincipalToInherit(), aInfo->mInfo.GetCsp());
+
+  for (size_t i = 0; i < mLoadingEntries.Length(); ++i) {
+    if (mLoadingEntries[i].mLoadId == aInfo->mLoadId) {
+      RefPtr<SessionHistoryEntry> loadingEntry = mLoadingEntries[i].mEntry;
+      loadingEntry->SetInfo(&newInfo);
+
+      if (IsTop()) {
+        // Only top level pages care about Get/SetPersist.
+        nsCOMPtr<nsIURI> uri;
+        aNewChannel->GetURI(getter_AddRefs(uri));
+        loadingEntry->SetPersist(
+            nsDocShell::ShouldAddToSessionHistory(uri, aNewChannel));
+      } else {
+        loadingEntry->SetIsSubFrame(aInfo->mInfo.IsSubFrame());
+      }
+      loadingEntry->SetDocshellID(GetHistoryID());
+      loadingEntry->SetIsDynamicallyAdded(CreatedDynamically());
+      return MakeUnique<LoadingSessionHistoryInfo>(loadingEntry, aInfo);
+    }
+  }
+  return nullptr;
+}
+
+using PrintPromise = CanonicalBrowsingContext::PrintPromise;
+#ifdef NS_PRINTING
+class PrintListenerAdapter final : public nsIWebProgressListener {
+ public:
+  explicit PrintListenerAdapter(PrintPromise::Private* aPromise)
+      : mPromise(aPromise) {}
+
+  NS_DECL_ISUPPORTS
+
+  // NS_DECL_NSIWEBPROGRESSLISTENER
+  NS_IMETHOD OnStateChange(nsIWebProgress* aWebProgress, nsIRequest* aRequest,
+                           uint32_t aStateFlags, nsresult aStatus) override {
+    if (aStateFlags & nsIWebProgressListener::STATE_STOP &&
+        aStateFlags & nsIWebProgressListener::STATE_IS_DOCUMENT && mPromise) {
+      mPromise->Resolve(true, __func__);
+      mPromise = nullptr;
+    }
+    return NS_OK;
+  }
+  NS_IMETHOD OnStatusChange(nsIWebProgress* aWebProgress, nsIRequest* aRequest,
+                            nsresult aStatus,
+                            const char16_t* aMessage) override {
+    if (aStatus != NS_OK && mPromise) {
+      mPromise->Reject(aStatus, __func__);
+      mPromise = nullptr;
+    }
+    return NS_OK;
+  }
+  NS_IMETHOD OnProgressChange(nsIWebProgress* aWebProgress,
+                              nsIRequest* aRequest, int32_t aCurSelfProgress,
+                              int32_t aMaxSelfProgress,
+                              int32_t aCurTotalProgress,
+                              int32_t aMaxTotalProgress) override {
+    return NS_OK;
+  }
+  NS_IMETHOD OnLocationChange(nsIWebProgress* aWebProgress,
+                              nsIRequest* aRequest, nsIURI* aLocation,
+                              uint32_t aFlags) override {
+    return NS_OK;
+  }
+  NS_IMETHOD OnSecurityChange(nsIWebProgress* aWebProgress,
+                              nsIRequest* aRequest, uint32_t aState) override {
+    return NS_OK;
+  }
+  NS_IMETHOD OnContentBlockingEvent(nsIWebProgress* aWebProgress,
+                                    nsIRequest* aRequest,
+                                    uint32_t aEvent) override {
+    return NS_OK;
+  }
+
+ private:
+  ~PrintListenerAdapter() = default;
+
+  RefPtr<PrintPromise::Private> mPromise;
+};
+
+NS_IMPL_ISUPPORTS(PrintListenerAdapter, nsIWebProgressListener)
+#endif
+
+already_AddRefed<Promise> CanonicalBrowsingContext::PrintJS(
+    nsIPrintSettings* aPrintSettings, ErrorResult& aRv) {
+  RefPtr<Promise> promise = Promise::Create(GetIncumbentGlobal(), aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return promise.forget();
+  }
+
+  Print(aPrintSettings)
+      ->Then(
+          GetCurrentSerialEventTarget(), __func__,
+          [promise](bool) { promise->MaybeResolveWithUndefined(); },
+          [promise](nsresult aResult) { promise->MaybeReject(aResult); });
+  return promise.forget();
+}
+
+RefPtr<PrintPromise> CanonicalBrowsingContext::Print(
+    nsIPrintSettings* aPrintSettings) {
+#ifndef NS_PRINTING
+  return PrintPromise::CreateAndReject(NS_ERROR_NOT_AVAILABLE, __func__);
+#else
+
+  auto promise = MakeRefPtr<PrintPromise::Private>(__func__);
+  auto listener = MakeRefPtr<PrintListenerAdapter>(promise);
+  if (IsInProcess()) {
+    RefPtr<nsGlobalWindowOuter> outerWindow =
+        nsGlobalWindowOuter::Cast(GetDOMWindow());
+    if (NS_WARN_IF(!outerWindow)) {
+      promise->Reject(NS_ERROR_FAILURE, __func__);
+      return promise;
+    }
+
+    ErrorResult rv;
+    outerWindow->Print(aPrintSettings,
+                       /* aRemotePrintJob = */ nullptr, listener,
+                       /* aDocShellToCloneInto = */ nullptr,
+                       nsGlobalWindowOuter::IsPreview::No,
+                       nsGlobalWindowOuter::IsForWindowDotPrint::No,
+                       /* aPrintPreviewCallback = */ nullptr, rv);
+    if (rv.Failed()) {
+      promise->Reject(rv.StealNSResult(), __func__);
+    }
+    return promise;
+  }
+
+  auto* browserParent = GetBrowserParent();
+  if (NS_WARN_IF(!browserParent)) {
+    promise->Reject(NS_ERROR_FAILURE, __func__);
+    return promise;
+  }
+
+  nsCOMPtr<nsIPrintSettingsService> printSettingsSvc =
+      do_GetService("@mozilla.org/gfx/printsettings-service;1");
+  if (NS_WARN_IF(!printSettingsSvc)) {
+    promise->Reject(NS_ERROR_FAILURE, __func__);
+    return promise;
+  }
+
+  nsresult rv;
+  nsCOMPtr<nsIPrintSettings> printSettings = aPrintSettings;
+  if (!printSettings) {
+    rv =
+        printSettingsSvc->CreateNewPrintSettings(getter_AddRefs(printSettings));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      promise->Reject(rv, __func__);
+      return promise;
+    }
+  }
+
+  embedding::PrintData printData;
+  rv = printSettingsSvc->SerializeToPrintData(printSettings, &printData);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    promise->Reject(rv, __func__);
+    return promise;
+  }
+
+  layout::RemotePrintJobParent* remotePrintJob =
+      new layout::RemotePrintJobParent(printSettings);
+  printData.remotePrintJob() =
+      browserParent->Manager()->SendPRemotePrintJobConstructor(remotePrintJob);
+
+  if (listener) {
+    remotePrintJob->RegisterListener(listener);
+  }
+
+  if (NS_WARN_IF(!browserParent->SendPrint(this, printData))) {
+    promise->Reject(NS_ERROR_FAILURE, __func__);
+  }
+  return promise.forget();
+#endif
+}
+
+void CanonicalBrowsingContext::CallOnAllTopDescendants(
+    const std::function<mozilla::CallState(CanonicalBrowsingContext*)>&
+        aCallback) {
+#ifdef DEBUG
+  RefPtr<CanonicalBrowsingContext> parent = GetParentCrossChromeBoundary();
+  MOZ_ASSERT(!parent, "Should only call on top chrome BC");
+#endif
+
+  nsTArray<RefPtr<BrowsingContextGroup>> groups;
+  BrowsingContextGroup::GetAllGroups(groups);
+  for (auto& browsingContextGroup : groups) {
+    for (auto& bc : browsingContextGroup->Toplevels()) {
+      if (bc == this) {
+        // Cannot be a descendent of myself so skip.
+        continue;
+      }
+
+      RefPtr<CanonicalBrowsingContext> top =
+          bc->Canonical()->TopCrossChromeBoundary();
+      if (top == this) {
+        if (aCallback(bc->Canonical()) == CallState::Stop) {
+          return;
+        }
+      }
+    }
+  }
+}
+
+void CanonicalBrowsingContext::SessionHistoryCommit(
+    uint64_t aLoadId, const nsID& aChangeID, uint32_t aLoadType, bool aPersist,
+    bool aCloneEntryChildren, bool aChannelExpired, uint32_t aCacheKey) {
+  MOZ_LOG(gSHLog, LogLevel::Verbose,
+          ("CanonicalBrowsingContext::SessionHistoryCommit %p %" PRIu64, this,
+           aLoadId));
+  MOZ_ASSERT(aLoadId != UINT64_MAX,
+             "Must not send special about:blank loadinfo to parent.");
+  for (size_t i = 0; i < mLoadingEntries.Length(); ++i) {
+    if (mLoadingEntries[i].mLoadId == aLoadId) {
+      nsSHistory* shistory = static_cast<nsSHistory*>(GetSessionHistory());
+      if (!shistory) {
+        SessionHistoryEntry::RemoveLoadId(aLoadId);
+        mLoadingEntries.RemoveElementAt(i);
+        return;
+      }
+
+      RefPtr<SessionHistoryEntry> newActiveEntry = mLoadingEntries[i].mEntry;
+      if (aCacheKey != 0) {
+        newActiveEntry->SetCacheKey(aCacheKey);
+      }
+
+      if (aChannelExpired) {
+        newActiveEntry->SharedInfo()->mExpired = true;
+      }
+
+      bool loadFromSessionHistory = !newActiveEntry->ForInitialLoad();
+      newActiveEntry->SetForInitialLoad(false);
+      SessionHistoryEntry::RemoveLoadId(aLoadId);
+      mLoadingEntries.RemoveElementAt(i);
+
+      int32_t indexOfHistoryLoad = -1;
+      if (loadFromSessionHistory) {
+        nsCOMPtr<nsISHEntry> root = nsSHistory::GetRootSHEntry(newActiveEntry);
+        indexOfHistoryLoad = shistory->GetIndexOfEntry(root);
+        if (indexOfHistoryLoad < 0) {
+          // Entry has been removed from the session history.
+          return;
+        }
+      }
+
+      CallerWillNotifyHistoryIndexAndLengthChanges caller(shistory);
+
+      // If there is a name in the new entry, clear the name of all contiguous
+      // entries. This is for https://html.spec.whatwg.org/#history-traversal
+      // Step 4.4.2.
+      nsAutoString nameOfNewEntry;
+      newActiveEntry->GetName(nameOfNewEntry);
+      if (!nameOfNewEntry.IsEmpty()) {
+        nsSHistory::WalkContiguousEntries(
+            newActiveEntry,
+            [](nsISHEntry* aEntry) { aEntry->SetName(EmptyString()); });
+      }
+
+      bool addEntry = ShouldUpdateSessionHistory(aLoadType);
+      if (IsTop()) {
+        if (mActiveEntry && !mActiveEntry->GetFrameLoader()) {
+          bool sharesDocument = true;
+          mActiveEntry->SharesDocumentWith(newActiveEntry, &sharesDocument);
+          if (!sharesDocument) {
+            // If the old page won't be in the bfcache,
+            // clear the dynamic entries.
+            RemoveDynEntriesFromActiveSessionHistoryEntry();
+          }
+        }
+
+        if (LOAD_TYPE_HAS_FLAGS(aLoadType,
+                                nsIWebNavigation::LOAD_FLAGS_REPLACE_HISTORY)) {
+          // Replace the current entry with the new entry.
+          int32_t index = shistory->GetIndexForReplace();
+
+          // If we're trying to replace an inexistant shistory entry then we
+          // should append instead.
+          addEntry = index < 0;
+          if (!addEntry) {
+            shistory->ReplaceEntry(index, newActiveEntry);
+          }
+          mActiveEntry = newActiveEntry;
+        } else if (LOAD_TYPE_HAS_FLAGS(
+                       aLoadType, nsIWebNavigation::LOAD_FLAGS_IS_REFRESH) &&
+                   !ShouldAddEntryForRefresh(newActiveEntry) && mActiveEntry) {
+          addEntry = false;
+          mActiveEntry->ReplaceWith(*newActiveEntry);
+        } else {
+          mActiveEntry = newActiveEntry;
+        }
+
+        if (loadFromSessionHistory) {
+          // XXX Synchronize browsing context tree and session history tree?
+          shistory->InternalSetRequestedIndex(indexOfHistoryLoad);
+          shistory->UpdateIndex();
+
+          if (IsTop()) {
+            mActiveEntry->SetWireframe(Nothing());
+          }
+        } else if (addEntry) {
+          shistory->AddEntry(mActiveEntry, aPersist);
+          shistory->InternalSetRequestedIndex(-1);
+        }
+      } else {
+        // FIXME The old implementations adds it to the parent's mLSHE if there
+        //       is one, need to figure out if that makes sense here (peterv
+        //       doesn't think it would).
+        if (loadFromSessionHistory) {
+          if (mActiveEntry) {
+            // mActiveEntry is null if we're loading iframes from session
+            // history while also parent page is loading from session history.
+            // In that case there isn't anything to sync.
+            mActiveEntry->SyncTreesForSubframeNavigation(newActiveEntry, Top(),
+                                                         this);
+          }
+          mActiveEntry = newActiveEntry;
+
+          shistory->InternalSetRequestedIndex(indexOfHistoryLoad);
+          // FIXME UpdateIndex() here may update index too early (but even the
+          //       old implementation seems to have similar issues).
+          shistory->UpdateIndex();
+        } else if (addEntry) {
+          if (mActiveEntry) {
+            if (LOAD_TYPE_HAS_FLAGS(
+                    aLoadType, nsIWebNavigation::LOAD_FLAGS_REPLACE_HISTORY) ||
+                (LOAD_TYPE_HAS_FLAGS(aLoadType,
+                                     nsIWebNavigation::LOAD_FLAGS_IS_REFRESH) &&
+                 !ShouldAddEntryForRefresh(newActiveEntry))) {
+              // FIXME We need to make sure that when we create the info we
+              //       make a copy of the shared state.
+              mActiveEntry->ReplaceWith(*newActiveEntry);
+            } else {
+              // AddChildSHEntryHelper does update the index of the session
+              // history!
+              shistory->AddChildSHEntryHelper(mActiveEntry, newActiveEntry,
+                                              Top(), aCloneEntryChildren);
+              mActiveEntry = newActiveEntry;
+            }
+          } else {
+            SessionHistoryEntry* parentEntry = GetParent()->mActiveEntry;
+            // XXX What should happen if parent doesn't have mActiveEntry?
+            //     Or can that even happen ever?
+            if (parentEntry) {
+              mActiveEntry = newActiveEntry;
+              // FIXME Using IsInProcess for aUseRemoteSubframes isn't quite
+              //       right, but aUseRemoteSubframes should be going away.
+              parentEntry->AddChild(
+                  mActiveEntry,
+                  CreatedDynamically() ? -1 : GetParent()->IndexOf(this),
+                  IsInProcess());
+            }
+          }
+          shistory->InternalSetRequestedIndex(-1);
+        }
+      }
+
+      ResetSHEntryHasUserInteractionCache();
+
+      HistoryCommitIndexAndLength(aChangeID, caller);
+
+      shistory->LogHistory();
+
+      return;
+    }
+    // XXX Should the loading entries before [i] be removed?
+  }
+  // FIXME Should we throw an error if we don't find an entry for
+  // aSessionHistoryEntryId?
+}
+
+already_AddRefed<nsDocShellLoadState> CanonicalBrowsingContext::CreateLoadInfo(
+    SessionHistoryEntry* aEntry) {
+  const SessionHistoryInfo& info = aEntry->Info();
+  RefPtr<nsDocShellLoadState> loadState(new nsDocShellLoadState(info.GetURI()));
+  info.FillLoadInfo(*loadState);
+  UniquePtr<LoadingSessionHistoryInfo> loadingInfo;
+  loadingInfo = MakeUnique<LoadingSessionHistoryInfo>(aEntry);
+  mLoadingEntries.AppendElement(
+      LoadingSessionHistoryEntry{loadingInfo->mLoadId, aEntry});
+  loadState->SetLoadingSessionHistoryInfo(std::move(loadingInfo));
+
+  return loadState.forget();
+}
+
+void CanonicalBrowsingContext::NotifyOnHistoryReload(
+    bool aForceReload, bool& aCanReload,
+    Maybe<NotNull<RefPtr<nsDocShellLoadState>>>& aLoadState,
+    Maybe<bool>& aReloadActiveEntry) {
+  MOZ_DIAGNOSTIC_ASSERT(!aLoadState);
+
+  aCanReload = true;
+  nsISHistory* shistory = GetSessionHistory();
+  NS_ENSURE_TRUE_VOID(shistory);
+
+  shistory->NotifyOnHistoryReload(&aCanReload);
+  if (!aCanReload) {
+    return;
+  }
+
+  if (mActiveEntry) {
+    aLoadState.emplace(WrapMovingNotNull(RefPtr{CreateLoadInfo(mActiveEntry)}));
+    aReloadActiveEntry.emplace(true);
+    if (aForceReload) {
+      shistory->RemoveFrameEntries(mActiveEntry);
+    }
+  } else if (!mLoadingEntries.IsEmpty()) {
+    const LoadingSessionHistoryEntry& loadingEntry =
+        mLoadingEntries.LastElement();
+    uint64_t loadId = loadingEntry.mLoadId;
+    aLoadState.emplace(
+        WrapMovingNotNull(RefPtr{CreateLoadInfo(loadingEntry.mEntry)}));
+    aReloadActiveEntry.emplace(false);
+    if (aForceReload) {
+      SessionHistoryEntry::LoadingEntry* entry =
+          SessionHistoryEntry::GetByLoadId(loadId);
+      if (entry) {
+        shistory->RemoveFrameEntries(entry->mEntry);
+      }
+    }
+  }
+
+  if (aLoadState) {
+    // Use 0 as the offset, since aLoadState will be be used for reload.
+    aLoadState.ref()->SetLoadIsFromSessionHistory(0,
+                                                  aReloadActiveEntry.value());
+  }
+  // If we don't have an active entry and we don't have a loading entry then
+  // the nsDocShell will create a load state based on its document.
+}
+
+void CanonicalBrowsingContext::SetActiveSessionHistoryEntry(
+    const Maybe<nsPoint>& aPreviousScrollPos, SessionHistoryInfo* aInfo,
+    uint32_t aLoadType, uint32_t aUpdatedCacheKey, const nsID& aChangeID) {
+  nsISHistory* shistory = GetSessionHistory();
+  if (!shistory) {
+    return;
+  }
+  CallerWillNotifyHistoryIndexAndLengthChanges caller(shistory);
+
+  RefPtr<SessionHistoryEntry> oldActiveEntry = mActiveEntry;
+  if (aPreviousScrollPos.isSome() && oldActiveEntry) {
+    oldActiveEntry->SetScrollPosition(aPreviousScrollPos.ref().x,
+                                      aPreviousScrollPos.ref().y);
+  }
+  mActiveEntry = new SessionHistoryEntry(aInfo);
+  mActiveEntry->SetDocshellID(GetHistoryID());
+  mActiveEntry->AdoptBFCacheEntry(oldActiveEntry);
+  if (aUpdatedCacheKey != 0) {
+    mActiveEntry->SharedInfo()->mCacheKey = aUpdatedCacheKey;
+  }
+
+  if (IsTop()) {
+    Maybe<int32_t> previousEntryIndex, loadedEntryIndex;
+    shistory->AddToRootSessionHistory(
+        true, oldActiveEntry, this, mActiveEntry, aLoadType,
+        nsDocShell::ShouldAddToSessionHistory(aInfo->GetURI(), nullptr),
+        &previousEntryIndex, &loadedEntryIndex);
+  } else {
+    if (oldActiveEntry) {
+      shistory->AddChildSHEntryHelper(oldActiveEntry, mActiveEntry, Top(),
+                                      true);
+    } else if (GetParent() && GetParent()->mActiveEntry) {
+      GetParent()->mActiveEntry->AddChild(
+          mActiveEntry, CreatedDynamically() ? -1 : GetParent()->IndexOf(this),
+          UseRemoteSubframes());
+    }
+  }
+
+  ResetSHEntryHasUserInteractionCache();
+
+  shistory->InternalSetRequestedIndex(-1);
+
+  // FIXME Need to do the equivalent of EvictContentViewersOrReplaceEntry.
+  HistoryCommitIndexAndLength(aChangeID, caller);
+
+  static_cast<nsSHistory*>(shistory)->LogHistory();
+}
+
+void CanonicalBrowsingContext::ReplaceActiveSessionHistoryEntry(
+    SessionHistoryInfo* aInfo) {
+  if (!mActiveEntry) {
+    return;
+  }
+
+  mActiveEntry->SetInfo(aInfo);
+  // Notify children of the update
+  nsSHistory* shistory = static_cast<nsSHistory*>(GetSessionHistory());
+  if (shistory) {
+    shistory->NotifyOnHistoryReplaceEntry();
+    shistory->UpdateRootBrowsingContextState();
+  }
+
+  ResetSHEntryHasUserInteractionCache();
+
+  if (IsTop()) {
+    mActiveEntry->SetWireframe(Nothing());
+  }
+
+  // FIXME Need to do the equivalent of EvictContentViewersOrReplaceEntry.
+}
+
+void CanonicalBrowsingContext::RemoveDynEntriesFromActiveSessionHistoryEntry() {
+  nsISHistory* shistory = GetSessionHistory();
+  // In theory shistory can be null here if the method is called right after
+  // CanonicalBrowsingContext::ReplacedBy call.
+  NS_ENSURE_TRUE_VOID(shistory);
+  nsCOMPtr<nsISHEntry> root = nsSHistory::GetRootSHEntry(mActiveEntry);
+  shistory->RemoveDynEntries(shistory->GetIndexOfEntry(root), mActiveEntry);
+}
+
+void CanonicalBrowsingContext::RemoveFromSessionHistory(const nsID& aChangeID) {
+  nsSHistory* shistory = static_cast<nsSHistory*>(GetSessionHistory());
+  if (shistory) {
+    CallerWillNotifyHistoryIndexAndLengthChanges caller(shistory);
+    nsCOMPtr<nsISHEntry> root = nsSHistory::GetRootSHEntry(mActiveEntry);
+    bool didRemove;
+    AutoTArray<nsID, 16> ids({GetHistoryID()});
+    shistory->RemoveEntries(ids, shistory->GetIndexOfEntry(root), &didRemove);
+    if (didRemove) {
+      RefPtr<BrowsingContext> rootBC = shistory->GetBrowsingContext();
+      if (rootBC) {
+        if (!rootBC->IsInProcess()) {
+          if (ContentParent* cp = rootBC->Canonical()->GetContentParent()) {
+            Unused << cp->SendDispatchLocationChangeEvent(rootBC);
+          }
+        } else if (rootBC->GetDocShell()) {
+          rootBC->GetDocShell()->DispatchLocationChangeEvent();
+        }
+      }
+    }
+    HistoryCommitIndexAndLength(aChangeID, caller);
+  }
+}
+
+Maybe<int32_t> CanonicalBrowsingContext::HistoryGo(
+    int32_t aOffset, uint64_t aHistoryEpoch, bool aRequireUserInteraction,
+    bool aUserActivation, Maybe<ContentParentId> aContentId) {
+  if (aRequireUserInteraction && aOffset != -1 && aOffset != 1) {
+    NS_ERROR(
+        "aRequireUserInteraction may only be used with an offset of -1 or 1");
+    return Nothing();
+  }
+
+  nsSHistory* shistory = static_cast<nsSHistory*>(GetSessionHistory());
+  if (!shistory) {
+    return Nothing();
+  }
+
+  CheckedInt<int32_t> index = shistory->GetRequestedIndex() >= 0
+                                  ? shistory->GetRequestedIndex()
+                                  : shistory->Index();
+  MOZ_LOG(gSHLog, LogLevel::Debug,
+          ("HistoryGo(%d->%d) epoch %" PRIu64 "/id %" PRIu64, aOffset,
+           (index + aOffset).value(), aHistoryEpoch,
+           (uint64_t)(aContentId.isSome() ? aContentId.value() : 0)));
+
+  while (true) {
+    index += aOffset;
+    if (!index.isValid()) {
+      MOZ_LOG(gSHLog, LogLevel::Debug, ("Invalid index"));
+      return Nothing();
+    }
+
+    // Check for user interaction if desired, except for the first and last
+    // history entries. We compare with >= to account for the case where
+    // aOffset >= length.
+    if (!aRequireUserInteraction || index.value() >= shistory->Length() - 1 ||
+        index.value() <= 0) {
+      break;
+    }
+    if (shistory->HasUserInteractionAtIndex(index.value())) {
+      break;
+    }
+  }
+
+  // Implement aborting additional history navigations from within the same
+  // event spin of the content process.
+
+  uint64_t epoch;
+  bool sameEpoch = false;
+  Maybe<ContentParentId> id;
+  shistory->GetEpoch(epoch, id);
+
+  if (aContentId == id && epoch >= aHistoryEpoch) {
+    sameEpoch = true;
+    MOZ_LOG(gSHLog, LogLevel::Debug, ("Same epoch/id"));
+  }
+  // Don't update the epoch until we know if the target index is valid
+
+  // GoToIndex checks that index is >= 0 and < length.
+  nsTArray<nsSHistory::LoadEntryResult> loadResults;
+  nsresult rv = shistory->GotoIndex(index.value(), loadResults, sameEpoch,
+                                    aOffset == 0, aUserActivation);
+  if (NS_FAILED(rv)) {
+    MOZ_LOG(gSHLog, LogLevel::Debug,
+            ("Dropping HistoryGo - bad index or same epoch (not in same doc)"));
+    return Nothing();
+  }
+  if (epoch < aHistoryEpoch || aContentId != id) {
+    MOZ_LOG(gSHLog, LogLevel::Debug, ("Set epoch"));
+    shistory->SetEpoch(aHistoryEpoch, aContentId);
+  }
+  int32_t requestedIndex = shistory->GetRequestedIndex();
+  nsSHistory::LoadURIs(loadResults);
+  return Some(requestedIndex);
+}
+
+JSObject* CanonicalBrowsingContext::WrapObject(
+    JSContext* aCx, JS::Handle<JSObject*> aGivenProto) {
+  return CanonicalBrowsingContext_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void CanonicalBrowsingContext::DispatchWheelZoomChange(bool aIncrease) {
+  Element* element = Top()->GetEmbedderElement();
+  if (!element) {
+    return;
+  }
+
+  auto event = aIncrease ? u"DoZoomEnlargeBy10"_ns : u"DoZoomReduceBy10"_ns;
+  auto dispatcher = MakeRefPtr<AsyncEventDispatcher>(
+      element, event, CanBubble::eYes, ChromeOnlyDispatch::eYes);
+  dispatcher->PostDOMEvent();
+}
+
+void CanonicalBrowsingContext::CanonicalDiscard() {
+  if (mTabMediaController) {
+    mTabMediaController->Shutdown();
+    mTabMediaController = nullptr;
+  }
+
+  if (mCurrentLoad) {
+    mCurrentLoad->Cancel(NS_BINDING_ABORTED,
+                         "CanonicalBrowsingContext::CanonicalDiscard"_ns);
+  }
+
+  if (mWebProgress) {
+    RefPtr<BrowsingContextWebProgress> progress = mWebProgress;
+    progress->ContextDiscarded();
+  }
+
+  if (IsTop()) {
+    BackgroundSessionStorageManager::RemoveManager(Id());
+  }
+
+  CancelSessionStoreUpdate();
+
+  if (UsePrivateBrowsing() && EverAttached() && IsContent()) {
+    DecreasePrivateCount();
+  }
+}
+
+void CanonicalBrowsingContext::CanonicalAttach() {
+  if (UsePrivateBrowsing() && IsContent()) {
+    IncreasePrivateCount();
+  }
+}
+
+void CanonicalBrowsingContext::AddPendingDiscard() {
+  MOZ_ASSERT(!mFullyDiscarded);
+  mPendingDiscards++;
+}
+
+void CanonicalBrowsingContext::RemovePendingDiscard() {
+  mPendingDiscards--;
+  if (!mPendingDiscards) {
+    mFullyDiscarded = true;
+    auto listeners = std::move(mFullyDiscardedListeners);
+    for (const auto& listener : listeners) {
+      listener(Id());
+    }
+  }
+}
+
+void CanonicalBrowsingContext::AddFinalDiscardListener(
+    std::function<void(uint64_t)>&& aListener) {
+  if (mFullyDiscarded) {
+    aListener(Id());
+    return;
+  }
+  mFullyDiscardedListeners.AppendElement(std::move(aListener));
+}
+
+void CanonicalBrowsingContext::SetForceAppWindowActive(bool aForceActive,
+                                                       ErrorResult& aRv) {
+  MOZ_DIAGNOSTIC_ASSERT(IsChrome());
+  MOZ_DIAGNOSTIC_ASSERT(IsTop());
+  if (!IsChrome() || !IsTop()) {
+    return aRv.ThrowNotAllowedError(
+        "You shouldn't need to force this BrowsingContext to be active, use "
+        ".isActive instead");
+  }
+  if (mForceAppWindowActive == aForceActive) {
+    return;
+  }
+  mForceAppWindowActive = aForceActive;
+  RecomputeAppWindowVisibility();
+}
+
+void CanonicalBrowsingContext::RecomputeAppWindowVisibility() {
+  MOZ_RELEASE_ASSERT(IsChrome());
+  MOZ_RELEASE_ASSERT(IsTop());
+
+  const bool isActive = [&] {
+    if (ForceAppWindowActive()) {
+      return true;
+    }
+    auto* docShell = GetDocShell();
+    if (NS_WARN_IF(!docShell)) {
+      return false;
+    }
+    nsCOMPtr<nsIWidget> widget;
+    nsDocShell::Cast(docShell)->GetMainWidget(getter_AddRefs(widget));
+    if (NS_WARN_IF(!widget)) {
+      return false;
+    }
+    if (widget->IsFullyOccluded() ||
+        widget->SizeMode() == nsSizeMode_Minimized) {
+      return false;
+    }
+    return true;
+  }();
+  SetIsActive(isActive, IgnoreErrors());
+}
+
+void CanonicalBrowsingContext::AdjustPrivateBrowsingCount(
+    bool aPrivateBrowsing) {
+  if (IsDiscarded() || !EverAttached() || IsChrome()) {
+    return;
+  }
+
+  MOZ_DIAGNOSTIC_ASSERT(aPrivateBrowsing == UsePrivateBrowsing());
+  if (aPrivateBrowsing) {
+    IncreasePrivateCount();
+  } else {
+    DecreasePrivateCount();
+  }
+}
+
+void CanonicalBrowsingContext::NotifyStartDelayedAutoplayMedia() {
+  WindowContext* windowContext = GetCurrentWindowContext();
+  if (!windowContext) {
+    return;
+  }
+
+  // As this function would only be called when user click the play icon on the
+  // tab bar. That's clear user intent to play, so gesture activate the window
+  // context so that the block-autoplay logic allows the media to autoplay.
+  windowContext->NotifyUserGestureActivation();
+  AUTOPLAY_LOG("NotifyStartDelayedAutoplayMedia for chrome bc 0x%08" PRIx64,
+               Id());
+  StartDelayedAutoplayMediaComponents();
+  // Notfiy all content browsing contexts which are related with the canonical
+  // browsing content tree to start delayed autoplay media.
+
+  Group()->EachParent([&](ContentParent* aParent) {
+    Unused << aParent->SendStartDelayedAutoplayMediaComponents(this);
+  });
+}
+
+void CanonicalBrowsingContext::NotifyMediaMutedChanged(bool aMuted,
+                                                       ErrorResult& aRv) {
+  MOZ_ASSERT(!GetParent(),
+             "Notify media mute change on non top-level context!");
+  SetMuted(aMuted, aRv);
+}
+
+uint32_t CanonicalBrowsingContext::CountSiteOrigins(
+    GlobalObject& aGlobal,
+    const Sequence<OwningNonNull<BrowsingContext>>& aRoots) {
+  nsTHashSet<nsCString> uniqueSiteOrigins;
+
+  for (const auto& root : aRoots) {
+    root->PreOrderWalk([&](BrowsingContext* aContext) {
+      WindowGlobalParent* windowGlobalParent =
+          aContext->Canonical()->GetCurrentWindowGlobal();
+      if (windowGlobalParent) {
+        nsIPrincipal* documentPrincipal =
+            windowGlobalParent->DocumentPrincipal();
+
+        bool isContentPrincipal = documentPrincipal->GetIsContentPrincipal();
+        if (isContentPrincipal) {
+          nsCString siteOrigin;
+          documentPrincipal->GetSiteOrigin(siteOrigin);
+          uniqueSiteOrigins.Insert(siteOrigin);
+        }
+      }
+    });
+  }
+
+  return uniqueSiteOrigins.Count();
+}
+
+/* static */
+bool CanonicalBrowsingContext::IsPrivateBrowsingActive() {
+  return gNumberOfPrivateContexts > 0;
+}
+
+void CanonicalBrowsingContext::UpdateMediaControlAction(
+    const MediaControlAction& aAction) {
+  if (IsDiscarded()) {
+    return;
+  }
+  ContentMediaControlKeyHandler::HandleMediaControlAction(this, aAction);
+  Group()->EachParent([&](ContentParent* aParent) {
+    Unused << aParent->SendUpdateMediaControlAction(this, aAction);
+  });
+}
+
+void CanonicalBrowsingContext::LoadURI(nsIURI* aURI,
+                                       const LoadURIOptions& aOptions,
+                                       ErrorResult& aError) {
+  RefPtr<nsDocShellLoadState> loadState;
+  nsresult rv = nsDocShellLoadState::CreateFromLoadURIOptions(
+      this, aURI, aOptions, getter_AddRefs(loadState));
+  MOZ_ASSERT(rv != NS_ERROR_MALFORMED_URI);
+
+  if (NS_FAILED(rv)) {
+    aError.Throw(rv);
+    return;
+  }
+
+  LoadURI(loadState, true);
+}
+
+void CanonicalBrowsingContext::FixupAndLoadURIString(
+    const nsAString& aURI, const LoadURIOptions& aOptions,
+    ErrorResult& aError) {
+  RefPtr<nsDocShellLoadState> loadState;
+  nsresult rv = nsDocShellLoadState::CreateFromLoadURIOptions(
+      this, aURI, aOptions, getter_AddRefs(loadState));
+
+  if (rv == NS_ERROR_MALFORMED_URI) {
+    DisplayLoadError(aURI);
+    return;
+  }
+
+  if (NS_FAILED(rv)) {
+    aError.Throw(rv);
+    return;
+  }
+
+  LoadURI(loadState, true);
+}
+
+void CanonicalBrowsingContext::GoBack(
+    const Optional<int32_t>& aCancelContentJSEpoch,
+    bool aRequireUserInteraction, bool aUserActivation) {
+  if (IsDiscarded()) {
+    return;
+  }
+
+  // Stop any known network loads if necessary.
+  if (mCurrentLoad) {
+    mCurrentLoad->Cancel(NS_BINDING_CANCELLED_OLD_LOAD, ""_ns);
+  }
+
+  if (RefPtr<nsDocShell> docShell = nsDocShell::Cast(GetDocShell())) {
+    if (aCancelContentJSEpoch.WasPassed()) {
+      docShell->SetCancelContentJSEpoch(aCancelContentJSEpoch.Value());
+    }
+    docShell->GoBack(aRequireUserInteraction, aUserActivation);
+  } else if (ContentParent* cp = GetContentParent()) {
+    Maybe<int32_t> cancelContentJSEpoch;
+    if (aCancelContentJSEpoch.WasPassed()) {
+      cancelContentJSEpoch = Some(aCancelContentJSEpoch.Value());
+    }
+    Unused << cp->SendGoBack(this, cancelContentJSEpoch,
+                             aRequireUserInteraction, aUserActivation);
+  }
+}
+void CanonicalBrowsingContext::GoForward(
+    const Optional<int32_t>& aCancelContentJSEpoch,
+    bool aRequireUserInteraction, bool aUserActivation) {
+  if (IsDiscarded()) {
+    return;
+  }
+
+  // Stop any known network loads if necessary.
+  if (mCurrentLoad) {
+    mCurrentLoad->Cancel(NS_BINDING_CANCELLED_OLD_LOAD, ""_ns);
+  }
+
+  if (RefPtr<nsDocShell> docShell = nsDocShell::Cast(GetDocShell())) {
+    if (aCancelContentJSEpoch.WasPassed()) {
+      docShell->SetCancelContentJSEpoch(aCancelContentJSEpoch.Value());
+    }
+    docShell->GoForward(aRequireUserInteraction, aUserActivation);
+  } else if (ContentParent* cp = GetContentParent()) {
+    Maybe<int32_t> cancelContentJSEpoch;
+    if (aCancelContentJSEpoch.WasPassed()) {
+      cancelContentJSEpoch.emplace(aCancelContentJSEpoch.Value());
+    }
+    Unused << cp->SendGoForward(this, cancelContentJSEpoch,
+                                aRequireUserInteraction, aUserActivation);
+  }
+}
+void CanonicalBrowsingContext::GoToIndex(
+    int32_t aIndex, const Optional<int32_t>& aCancelContentJSEpoch,
+    bool aUserActivation) {
+  if (IsDiscarded()) {
+    return;
+  }
+
+  // Stop any known network loads if necessary.
+  if (mCurrentLoad) {
+    mCurrentLoad->Cancel(NS_BINDING_CANCELLED_OLD_LOAD, ""_ns);
+  }
+
+  if (RefPtr<nsDocShell> docShell = nsDocShell::Cast(GetDocShell())) {
+    if (aCancelContentJSEpoch.WasPassed()) {
+      docShell->SetCancelContentJSEpoch(aCancelContentJSEpoch.Value());
+    }
+    docShell->GotoIndex(aIndex, aUserActivation);
+  } else if (ContentParent* cp = GetContentParent()) {
+    Maybe<int32_t> cancelContentJSEpoch;
+    if (aCancelContentJSEpoch.WasPassed()) {
+      cancelContentJSEpoch.emplace(aCancelContentJSEpoch.Value());
+    }
+    Unused << cp->SendGoToIndex(this, aIndex, cancelContentJSEpoch,
+                                aUserActivation);
+  }
+}
+void CanonicalBrowsingContext::Reload(uint32_t aReloadFlags) {
+  if (IsDiscarded()) {
+    return;
+  }
+
+  // Stop any known network loads if necessary.
+  if (mCurrentLoad) {
+    mCurrentLoad->Cancel(NS_BINDING_CANCELLED_OLD_LOAD, ""_ns);
+  }
+
+  if (RefPtr<nsDocShell> docShell = nsDocShell::Cast(GetDocShell())) {
+    docShell->Reload(aReloadFlags);
+  } else if (ContentParent* cp = GetContentParent()) {
+    Unused << cp->SendReload(this, aReloadFlags);
+  }
+}
+
+void CanonicalBrowsingContext::Stop(uint32_t aStopFlags) {
+  if (IsDiscarded()) {
+    return;
+  }
+
+  // Stop any known network loads if necessary.
+  if (mCurrentLoad && (aStopFlags & nsIWebNavigation::STOP_NETWORK)) {
+    mCurrentLoad->Cancel(NS_BINDING_ABORTED,
+                         "CanonicalBrowsingContext::Stop"_ns);
+  }
+
+  // Ask the docshell to stop to handle loads that haven't
+  // yet reached here, as well as non-network activity.
+  if (auto* docShell = nsDocShell::Cast(GetDocShell())) {
+    docShell->Stop(aStopFlags);
+  } else if (ContentParent* cp = GetContentParent()) {
+    Unused << cp->SendStopLoad(this, aStopFlags);
+  }
+}
+
+void CanonicalBrowsingContext::PendingRemotenessChange::ProcessLaunched() {
+  if (!mPromise) {
+    return;
+  }
+
+  if (mContentParent) {
+    // If our new content process is still unloading from a previous process
+    // switch, wait for that unload to complete before continuing.
+    auto found = mTarget->FindUnloadingHost(mContentParent->ChildID());
+    if (found != mTarget->mUnloadingHosts.end()) {
+      found->mCallbacks.AppendElement(
+          [self = RefPtr{this}]() { self->ProcessReady(); });
+      return;
+    }
+  }
+
+  ProcessReady();
+}
+
+void CanonicalBrowsingContext::PendingRemotenessChange::ProcessReady() {
+  if (!mPromise) {
+    return;
+  }
+
+  MOZ_ASSERT(!mProcessReady);
+  mProcessReady = true;
+  MaybeFinish();
+}
+
+void CanonicalBrowsingContext::PendingRemotenessChange::MaybeFinish() {
+  if (!mPromise) {
+    return;
+  }
+
+  if (!mProcessReady || mWaitingForPrepareToChange) {
+    return;
+  }
+
+  // If this BrowsingContext is embedded within the parent process, perform the
+  // process switch directly.
+  nsresult rv = mTarget->IsTopContent() ? FinishTopContent() : FinishSubframe();
+  if (NS_FAILED(rv)) {
+    NS_WARNING("Error finishing PendingRemotenessChange!");
+    Cancel(rv);
+  } else {
+    Clear();
+  }
+}
+
+// Logic for finishing a toplevel process change embedded within the parent
+// process. Due to frontend integration the logic differs substantially from
+// subframe process switches, and is handled separately.
+nsresult CanonicalBrowsingContext::PendingRemotenessChange::FinishTopContent() {
+  MOZ_DIAGNOSTIC_ASSERT(mTarget->IsTop(),
+                        "We shouldn't be trying to change the remoteness of "
+                        "non-remote iframes");
+
+  // Abort if our ContentParent died while process switching.
+  if (mContentParent && NS_WARN_IF(mContentParent->IsShuttingDown())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // While process switching, we need to check if any of our ancestors are
+  // discarded or no longer current, in which case the process switch needs to
+  // be aborted.
+  RefPtr<CanonicalBrowsingContext> target(mTarget);
+  if (target->IsDiscarded() || !target->AncestorsAreCurrent()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  Element* browserElement = target->GetEmbedderElement();
+  if (!browserElement) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIBrowser> browser = browserElement->AsBrowser();
+  if (!browser) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<nsFrameLoaderOwner> frameLoaderOwner = do_QueryObject(browserElement);
+  MOZ_RELEASE_ASSERT(frameLoaderOwner,
+                     "embedder browser must be nsFrameLoaderOwner");
+
+  // If we're process switching a browsing context in private browsing
+  // mode we might decrease the private browsing count to '0', which
+  // would make us fire "last-pb-context-exited" and drop the private
+  // session. To prevent that we artificially increment the number of
+  // private browsing contexts with '1' until the process switch is done.
+  bool usePrivateBrowsing = mTarget->UsePrivateBrowsing();
+  if (usePrivateBrowsing) {
+    IncreasePrivateCount();
+  }
+
+  auto restorePrivateCount = MakeScopeExit([usePrivateBrowsing]() {
+    if (usePrivateBrowsing) {
+      DecreasePrivateCount();
+    }
+  });
+
+  // Tell frontend code that this browser element is about to change process.
+  nsresult rv = browser->BeforeChangeRemoteness();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // Some frontend code checks the value of the `remote` attribute on the
+  // browser to determine if it is remote, so update the value.
+  browserElement->SetAttr(kNameSpaceID_None, nsGkAtoms::remote,
+                          mContentParent ? u"true"_ns : u"false"_ns,
+                          /* notify */ true);
+
+  // The process has been created, hand off to nsFrameLoaderOwner to finish
+  // the process switch.
+  ErrorResult error;
+  frameLoaderOwner->ChangeRemotenessToProcess(mContentParent, mOptions,
+                                              mSpecificGroup, error);
+  if (error.Failed()) {
+    return error.StealNSResult();
+  }
+
+  // Tell frontend the load is done.
+  bool loadResumed = false;
+  rv = browser->FinishChangeRemoteness(mPendingSwitchId, &loadResumed);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // We did it! The process switch is complete.
+  RefPtr<nsFrameLoader> frameLoader = frameLoaderOwner->GetFrameLoader();
+  RefPtr<BrowserParent> newBrowser = frameLoader->GetBrowserParent();
+  if (!newBrowser) {
+    if (mContentParent) {
+      // Failed to create the BrowserParent somehow! Abort the process switch
+      // attempt.
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    if (!loadResumed) {
+      RefPtr<nsDocShell> newDocShell = frameLoader->GetDocShell(error);
+      if (error.Failed()) {
+        return error.StealNSResult();
+      }
+
+      rv = newDocShell->ResumeRedirectedLoad(mPendingSwitchId,
+                                             /* aHistoryIndex */ -1);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+    }
+  } else if (!loadResumed) {
+    newBrowser->ResumeLoad(mPendingSwitchId);
+  }
+
+  mPromise->Resolve(newBrowser, __func__);
+  return NS_OK;
+}
+
+nsresult CanonicalBrowsingContext::PendingRemotenessChange::FinishSubframe() {
+  MOZ_DIAGNOSTIC_ASSERT(!mOptions.mReplaceBrowsingContext,
+                        "Cannot replace BC for subframe");
+  MOZ_DIAGNOSTIC_ASSERT(!mTarget->IsTop());
+
+  // While process switching, we need to check if any of our ancestors are
+  // discarded or no longer current, in which case the process switch needs to
+  // be aborted.
+  RefPtr<CanonicalBrowsingContext> target(mTarget);
+  if (target->IsDiscarded() || !target->AncestorsAreCurrent()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (NS_WARN_IF(!mContentParent)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<WindowGlobalParent> embedderWindow = target->GetParentWindowContext();
+  if (NS_WARN_IF(!embedderWindow) || NS_WARN_IF(!embedderWindow->CanSend())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<BrowserParent> embedderBrowser = embedderWindow->GetBrowserParent();
+  if (NS_WARN_IF(!embedderBrowser)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // If we're creating a new remote browser, and the host process is already
+  // dead, abort the process switch.
+  if (mContentParent != embedderBrowser->Manager() &&
+      NS_WARN_IF(mContentParent->IsShuttingDown())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<BrowserParent> oldBrowser = target->GetBrowserParent();
+  target->SetCurrentBrowserParent(nullptr);
+
+  // If we were in a remote frame, trigger unloading of the remote window. The
+  // previous BrowserParent is registered in `mUnloadingHosts` and will only be
+  // cleared when the BrowserParent is fully destroyed.
+  bool wasRemote = oldBrowser && oldBrowser->GetBrowsingContext() == target;
+  if (wasRemote) {
+    MOZ_DIAGNOSTIC_ASSERT(oldBrowser != embedderBrowser);
+    MOZ_DIAGNOSTIC_ASSERT(oldBrowser->IsDestroyed() ||
+                          oldBrowser->GetBrowserBridgeParent());
+
+    // `oldBrowser` will clear the `UnloadingHost` status once the actor has
+    // been destroyed.
+    if (oldBrowser->CanSend()) {
+      target->StartUnloadingHost(oldBrowser->Manager()->ChildID());
+      Unused << oldBrowser->SendWillChangeProcess();
+      oldBrowser->Destroy();
+    }
+  }
+
+  // Update which process is considered the current owner
+  target->SetOwnerProcessId(mContentParent->ChildID());
+
+  // If we're switching from remote to local, we don't need to create a
+  // BrowserBridge, and can instead perform the switch directly.
+  if (mContentParent == embedderBrowser->Manager()) {
+    MOZ_DIAGNOSTIC_ASSERT(
+        mPendingSwitchId,
+        "We always have a PendingSwitchId, except for print-preview loads, "
+        "which will never perform a process-switch to being in-process with "
+        "their embedder");
+    MOZ_DIAGNOSTIC_ASSERT(wasRemote,
+                          "Attempt to process-switch from local to local?");
+
+    target->SetCurrentBrowserParent(embedderBrowser);
+    Unused << embedderWindow->SendMakeFrameLocal(target, mPendingSwitchId);
+    mPromise->Resolve(embedderBrowser, __func__);
+    return NS_OK;
+  }
+
+  // The BrowsingContext will be remote, either as an already-remote frame
+  // changing processes, or as a local frame becoming remote. Construct a new
+  // BrowserBridgeParent to host the remote content.
+  target->SetCurrentBrowserParent(nullptr);
+
+  MOZ_DIAGNOSTIC_ASSERT(target->UseRemoteTabs() && target->UseRemoteSubframes(),
+                        "Not supported without fission");
+  uint32_t chromeFlags = nsIWebBrowserChrome::CHROME_REMOTE_WINDOW |
+                         nsIWebBrowserChrome::CHROME_FISSION_WINDOW;
+  if (target->UsePrivateBrowsing()) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW;
+  }
+
+  nsCOMPtr<nsIPrincipal> initialPrincipal =
+      NullPrincipal::Create(target->OriginAttributesRef());
+  WindowGlobalInit windowInit =
+      WindowGlobalActor::AboutBlankInitializer(target, initialPrincipal);
+
+  // Create and initialize our new BrowserBridgeParent.
+  TabId tabId(nsContentUtils::GenerateTabId());
+  RefPtr<BrowserBridgeParent> bridge = new BrowserBridgeParent();
+  nsresult rv = bridge->InitWithProcess(embedderBrowser, mContentParent,
+                                        windowInit, chromeFlags, tabId);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    // If we've already destroyed our previous document, make a best-effort
+    // attempt to recover from this failure and show the crashed tab UI. We only
+    // do this in the previously-remote case, as previously in-process frames
+    // will have their navigation cancelled, and will remain visible.
+    if (wasRemote) {
+      target->ShowSubframeCrashedUI(oldBrowser->GetBrowserBridgeParent());
+    }
+    return rv;
+  }
+
+  // Tell the embedder process a remoteness change is in-process. When this is
+  // acknowledged, reset the in-flight ID if it used to be an in-process load.
+  RefPtr<BrowserParent> newBrowser = bridge->GetBrowserParent();
+  {
+    // If we weren't remote, mark our embedder window browser as unloading until
+    // our embedder process has acked our MakeFrameRemote message.
+    Maybe<uint64_t> clearChildID;
+    if (!wasRemote) {
+      clearChildID = Some(embedderBrowser->Manager()->ChildID());
+      target->StartUnloadingHost(*clearChildID);
+    }
+    auto callback = [target, clearChildID](auto&&) {
+      if (clearChildID) {
+        target->ClearUnloadingHost(*clearChildID);
+      }
+    };
+
+    ManagedEndpoint<PBrowserBridgeChild> endpoint =
+        embedderBrowser->OpenPBrowserBridgeEndpoint(bridge);
+    MOZ_DIAGNOSTIC_ASSERT(endpoint.IsValid());
+    embedderWindow->SendMakeFrameRemote(target, std::move(endpoint), tabId,
+                                        newBrowser->GetLayersId(), callback,
+                                        callback);
+  }
+
+  // Resume the pending load in our new process.
+  if (mPendingSwitchId) {
+    newBrowser->ResumeLoad(mPendingSwitchId);
+  }
+
+  // We did it! The process switch is complete.
+  mPromise->Resolve(newBrowser, __func__);
+  return NS_OK;
+}
+
+void CanonicalBrowsingContext::PendingRemotenessChange::Cancel(nsresult aRv) {
+  if (!mPromise) {
+    return;
+  }
+
+  mPromise->Reject(aRv, __func__);
+  Clear();
+}
+
+void CanonicalBrowsingContext::PendingRemotenessChange::Clear() {
+  // Make sure we don't die while we're doing cleanup.
+  RefPtr<PendingRemotenessChange> kungFuDeathGrip(this);
+  if (mTarget) {
+    MOZ_DIAGNOSTIC_ASSERT(mTarget->mPendingRemotenessChange == this);
+    mTarget->mPendingRemotenessChange = nullptr;
+  }
+
+  // When this PendingRemotenessChange was created, it was given a
+  // `mContentParent`.
+  if (mContentParent) {
+    mContentParent->RemoveKeepAlive();
+    mContentParent = nullptr;
+  }
+
+  // If we were given a specific group, stop keeping that group alive manually.
+  if (mSpecificGroup) {
+    mSpecificGroup->RemoveKeepAlive();
+    mSpecificGroup = nullptr;
+  }
+
+  mPromise = nullptr;
+  mTarget = nullptr;
+}
+
+CanonicalBrowsingContext::PendingRemotenessChange::PendingRemotenessChange(
+    CanonicalBrowsingContext* aTarget, RemotenessPromise::Private* aPromise,
+    uint64_t aPendingSwitchId, const NavigationIsolationOptions& aOptions)
+    : mTarget(aTarget),
+      mPromise(aPromise),
+      mPendingSwitchId(aPendingSwitchId),
+      mOptions(aOptions) {}
+
+CanonicalBrowsingContext::PendingRemotenessChange::~PendingRemotenessChange() {
+  MOZ_ASSERT(!mPromise && !mTarget && !mContentParent && !mSpecificGroup,
+             "should've already been Cancel() or Complete()-ed");
+}
+
+BrowserParent* CanonicalBrowsingContext::GetBrowserParent() const {
+  return mCurrentBrowserParent;
+}
+
+void CanonicalBrowsingContext::SetCurrentBrowserParent(
+    BrowserParent* aBrowserParent) {
+  MOZ_DIAGNOSTIC_ASSERT(!mCurrentBrowserParent || !aBrowserParent,
+                        "BrowsingContext already has a current BrowserParent!");
+  MOZ_DIAGNOSTIC_ASSERT_IF(aBrowserParent, aBrowserParent->CanSend());
+  MOZ_DIAGNOSTIC_ASSERT_IF(aBrowserParent,
+                           aBrowserParent->Manager()->ChildID() == mProcessId);
+
+  // BrowserParent must either be directly for this BrowsingContext, or the
+  // manager out our embedder WindowGlobal.
+  MOZ_DIAGNOSTIC_ASSERT_IF(
+      aBrowserParent && aBrowserParent->GetBrowsingContext() != this,
+      GetParentWindowContext() &&
+          GetParentWindowContext()->Manager() == aBrowserParent);
+
+  mCurrentBrowserParent = aBrowserParent;
+}
+
+RefPtr<CanonicalBrowsingContext::RemotenessPromise>
+CanonicalBrowsingContext::ChangeRemoteness(
+    const NavigationIsolationOptions& aOptions, uint64_t aPendingSwitchId) {
+  MOZ_DIAGNOSTIC_ASSERT(IsContent(),
+                        "cannot change the process of chrome contexts");
+  MOZ_DIAGNOSTIC_ASSERT(
+      IsTop() == IsEmbeddedInProcess(0),
+      "toplevel content must be embedded in the parent process");
+  MOZ_DIAGNOSTIC_ASSERT(!aOptions.mReplaceBrowsingContext || IsTop(),
+                        "Cannot replace BrowsingContext for subframes");
+  MOZ_DIAGNOSTIC_ASSERT(
+      aOptions.mSpecificGroupId == 0 || aOptions.mReplaceBrowsingContext,
+      "Cannot specify group ID unless replacing BC");
+  MOZ_DIAGNOSTIC_ASSERT(aPendingSwitchId || !IsTop(),
+                        "Should always have aPendingSwitchId for top-level "
+                        "frames");
+
+  if (!AncestorsAreCurrent()) {
+    NS_WARNING("An ancestor context is no longer current");
+    return RemotenessPromise::CreateAndReject(NS_ERROR_FAILURE, __func__);
+  }
+
+  // Ensure our embedder hasn't been destroyed or asked to shutdown already.
+  RefPtr<WindowGlobalParent> embedderWindowGlobal = GetEmbedderWindowGlobal();
+  if (!embedderWindowGlobal) {
+    NS_WARNING("Non-embedded BrowsingContext");
+    return RemotenessPromise::CreateAndReject(NS_ERROR_UNEXPECTED, __func__);
+  }
+
+  if (!embedderWindowGlobal->CanSend()) {
+    NS_WARNING("Embedder already been destroyed.");
+    return RemotenessPromise::CreateAndReject(NS_ERROR_NOT_AVAILABLE, __func__);
+  }
+
+  RefPtr<BrowserParent> embedderBrowser =
+      embedderWindowGlobal->GetBrowserParent();
+  if (embedderBrowser && embedderBrowser->Manager()->IsShuttingDown()) {
+    NS_WARNING("Embedder already asked to shutdown.");
+    return RemotenessPromise::CreateAndReject(NS_ERROR_NOT_AVAILABLE, __func__);
+  }
+
+  if (aOptions.mRemoteType.IsEmpty() && (!IsTop() || !GetEmbedderElement())) {
+    NS_WARNING("Cannot load non-remote subframes");
+    return RemotenessPromise::CreateAndReject(NS_ERROR_FAILURE, __func__);
+  }
+
+  // Cancel ongoing remoteness changes.
+  if (mPendingRemotenessChange) {
+    mPendingRemotenessChange->Cancel(NS_ERROR_ABORT);
+    MOZ_DIAGNOSTIC_ASSERT(!mPendingRemotenessChange, "Should have cleared");
+  }
+
+  auto promise = MakeRefPtr<RemotenessPromise::Private>(__func__);
+  promise->UseDirectTaskDispatch(__func__);
+
+  RefPtr<PendingRemotenessChange> change =
+      new PendingRemotenessChange(this, promise, aPendingSwitchId, aOptions);
+  mPendingRemotenessChange = change;
+
+  // If a specific BrowsingContextGroup ID was specified for this load, make
+  // sure to keep it alive until the process switch is completed.
+  if (aOptions.mSpecificGroupId) {
+    change->mSpecificGroup =
+        BrowsingContextGroup::GetOrCreate(aOptions.mSpecificGroupId);
+    change->mSpecificGroup->AddKeepAlive();
+  }
+
+  // Call `prepareToChangeRemoteness` in parallel with starting a new process
+  // for <browser> loads.
+  if (IsTop() && GetEmbedderElement()) {
+    nsCOMPtr<nsIBrowser> browser = GetEmbedderElement()->AsBrowser();
+    if (!browser) {
+      change->Cancel(NS_ERROR_FAILURE);
+      return promise.forget();
+    }
+
+    RefPtr<Promise> blocker;
+    nsresult rv = browser->PrepareToChangeRemoteness(getter_AddRefs(blocker));
+    if (NS_FAILED(rv)) {
+      change->Cancel(rv);
+      return promise.forget();
+    }
+
+    // Mark prepareToChange as unresolved, and wait for it to become resolved.
+    if (blocker && blocker->State() != Promise::PromiseState::Resolved) {
+      change->mWaitingForPrepareToChange = true;
+      RefPtr<DomPromiseListener> listener = new DomPromiseListener(
+          [change](JSContext* aCx, JS::Handle<JS::Value> aValue) {
+            change->mWaitingForPrepareToChange = false;
+            change->MaybeFinish();
+          },
+          [change](nsresult aRv) { change->Cancel(aRv); });
+      blocker->AppendNativeHandler(listener);
+    }
+  }
+
+  // Switching a subframe to be local within it's embedding process.
+  if (embedderBrowser &&
+      aOptions.mRemoteType == embedderBrowser->Manager()->GetRemoteType()) {
+    MOZ_DIAGNOSTIC_ASSERT(
+        aPendingSwitchId,
+        "We always have a PendingSwitchId, except for print-preview loads, "
+        "which will never perform a process-switch to being in-process with "
+        "their embedder");
+    MOZ_DIAGNOSTIC_ASSERT(!aOptions.mReplaceBrowsingContext);
+    MOZ_DIAGNOSTIC_ASSERT(!aOptions.mRemoteType.IsEmpty());
+    MOZ_DIAGNOSTIC_ASSERT(!change->mWaitingForPrepareToChange);
+    MOZ_DIAGNOSTIC_ASSERT(!change->mSpecificGroup);
+
+    // Switching to local, so we don't need to create a new process, and will
+    // instead use our embedder process.
+    change->mContentParent = embedderBrowser->Manager();
+    change->mContentParent->AddKeepAlive();
+    change->ProcessLaunched();
+    return promise.forget();
+  }
+
+  // Switching to the parent process.
+  if (aOptions.mRemoteType.IsEmpty()) {
+    change->ProcessLaunched();
+    return promise.forget();
+  }
+
+  // If we're aiming to end up in a new process of the same type as our old
+  // process, and then putting our previous document in the BFCache, try to stay
+  // in the same process to avoid creating new processes unnecessarily.
+  RefPtr<ContentParent> existingProcess = GetContentParent();
+  if (existingProcess && !existingProcess->IsShuttingDown() &&
+      aOptions.mReplaceBrowsingContext &&
+      aOptions.mRemoteType == existingProcess->GetRemoteType()) {
+    change->mContentParent = existingProcess;
+    change->mContentParent->AddKeepAlive();
+    change->ProcessLaunched();
+    return promise.forget();
+  }
+
+  // Try to predict which BrowsingContextGroup will be used for the final load
+  // in this BrowsingContext. This has to be accurate if switching into an
+  // existing group, as it will control what pool of processes will be used
+  // for process selection.
+  //
+  // It's _technically_ OK to provide a group here if we're actually going to
+  // switch into a brand new group, though it's sub-optimal, as it can
+  // restrict the set of processes we're using.
+  BrowsingContextGroup* finalGroup =
+      aOptions.mReplaceBrowsingContext ? change->mSpecificGroup.get() : Group();
+
+  bool preferUsed =
+      StaticPrefs::browser_tabs_remote_subframesPreferUsed() && !IsTop();
+
+  change->mContentParent = ContentParent::GetNewOrUsedLaunchingBrowserProcess(
+      /* aRemoteType = */ aOptions.mRemoteType,
+      /* aGroup = */ finalGroup,
+      /* aPriority = */ hal::PROCESS_PRIORITY_FOREGROUND,
+      /* aPreferUsed = */ preferUsed);
+  if (!change->mContentParent) {
+    change->Cancel(NS_ERROR_FAILURE);
+    return promise.forget();
+  }
+
+  // Add a KeepAlive used by this ContentParent, which will be cleared when
+  // the change is complete. This should prevent the process dying before
+  // we're ready to use it.
+  change->mContentParent->AddKeepAlive();
+  if (change->mContentParent->IsLaunching()) {
+    change->mContentParent->WaitForLaunchAsync()->Then(
+        GetMainThreadSerialEventTarget(), __func__,
+        [change](ContentParent*) { change->ProcessLaunched(); },
+        [change]() { change->Cancel(NS_ERROR_FAILURE); });
+  } else {
+    change->ProcessLaunched();
+  }
+  return promise.forget();
+}
+
+void CanonicalBrowsingContext::MaybeSetPermanentKey(Element* aEmbedder) {
+  MOZ_DIAGNOSTIC_ASSERT(IsTop());
+
+  if (aEmbedder) {
+    if (nsCOMPtr<nsIBrowser> browser = aEmbedder->AsBrowser()) {
+      JS::Rooted<JS::Value> key(RootingCx());
+      if (NS_SUCCEEDED(browser->GetPermanentKey(&key)) && key.isObject()) {
+        mPermanentKey = key;
+      }
+    }
+  }
+}
+
+MediaController* CanonicalBrowsingContext::GetMediaController() {
+  // We would only create one media controller per tab, so accessing the
+  // controller via the top-level browsing context.
+  if (GetParent()) {
+    return Cast(Top())->GetMediaController();
+  }
+
+  MOZ_ASSERT(!GetParent(),
+             "Must access the controller from the top-level browsing context!");
+  // Only content browsing context can create media controller, we won't create
+  // controller for chrome document, such as the browser UI.
+  if (!mTabMediaController && !IsDiscarded() && IsContent()) {
+    mTabMediaController = new MediaController(Id());
+  }
+  return mTabMediaController;
+}
+
+bool CanonicalBrowsingContext::HasCreatedMediaController() const {
+  return !!mTabMediaController;
+}
+
+bool CanonicalBrowsingContext::SupportsLoadingInParent(
+    nsDocShellLoadState* aLoadState, uint64_t* aOuterWindowId) {
+  // We currently don't support initiating loads in the parent when they are
+  // watched by devtools. This is because devtools tracks loads using content
+  // process notifications, which happens after the load is initiated in this
+  // case. Devtools clears all prior requests when it detects a new navigation,
+  // so it drops the main document load that happened here.
+  if (WatchedByDevTools()) {
+    return false;
+  }
+
+  // Session-history-in-parent implementation relies currently on getting a
+  // round trip through a child process.
+  if (aLoadState->LoadIsFromSessionHistory()) {
+    return false;
+  }
+
+  // DocumentChannel currently only supports connecting channels into the
+  // content process, so we can only support schemes that will always be loaded
+  // there for now. Restrict to just http(s) for simplicity.
+  if (!net::SchemeIsHTTP(aLoadState->URI()) &&
+      !net::SchemeIsHTTPS(aLoadState->URI())) {
+    return false;
+  }
+
+  if (WindowGlobalParent* global = GetCurrentWindowGlobal()) {
+    nsCOMPtr<nsIURI> currentURI = global->GetDocumentURI();
+    if (currentURI) {
+      bool newURIHasRef = false;
+      aLoadState->URI()->GetHasRef(&newURIHasRef);
+      bool equalsExceptRef = false;
+      aLoadState->URI()->EqualsExceptRef(currentURI, &equalsExceptRef);
+
+      if (equalsExceptRef && newURIHasRef) {
+        // This navigation is same-doc WRT the current one, we should pass it
+        // down to the docshell to be handled.
+        return false;
+      }
+    }
+    // If the current document has a beforeunload listener, then we need to
+    // start the load in that process after we fire the event.
+    if (global->HasBeforeUnload()) {
+      return false;
+    }
+
+    *aOuterWindowId = global->OuterWindowId();
+  }
+  return true;
+}
+
+bool CanonicalBrowsingContext::LoadInParent(nsDocShellLoadState* aLoadState,
+                                            bool aSetNavigating) {
+  // We currently only support starting loads directly from the
+  // CanonicalBrowsingContext for top-level BCs.
+  // We currently only support starting loads directly from the
+  // CanonicalBrowsingContext for top-level BCs.
+  if (!IsTopContent() || !GetContentParent() ||
+      !StaticPrefs::browser_tabs_documentchannel_parent_controlled()) {
+    return false;
+  }
+
+  uint64_t outerWindowId = 0;
+  if (!SupportsLoadingInParent(aLoadState, &outerWindowId)) {
+    return false;
+  }
+
+  MOZ_ASSERT(!net::SchemeIsJavascript(aLoadState->URI()));
+
+  MOZ_ALWAYS_SUCCEEDS(
+      SetParentInitiatedNavigationEpoch(++gParentInitiatedNavigationEpoch));
+  // Note: If successful, this will recurse into StartDocumentLoad and
+  // set mCurrentLoad to the DocumentLoadListener instance created.
+  // Ideally in the future we will only start loads from here, and we can
+  // just set this directly instead.
+  return net::DocumentLoadListener::LoadInParent(this, aLoadState,
+                                                 aSetNavigating);
+}
+
+bool CanonicalBrowsingContext::AttemptSpeculativeLoadInParent(
+    nsDocShellLoadState* aLoadState) {
+  // We currently only support starting loads directly from the
+  // CanonicalBrowsingContext for top-level BCs.
+  // We currently only support starting loads directly from the
+  // CanonicalBrowsingContext for top-level BCs.
+  if (!IsTopContent() || !GetContentParent() ||
+      (StaticPrefs::browser_tabs_documentchannel_parent_controlled())) {
+    return false;
+  }
+
+  uint64_t outerWindowId = 0;
+  if (!SupportsLoadingInParent(aLoadState, &outerWindowId)) {
+    return false;
+  }
+
+  // If we successfully open the DocumentChannel, then it'll register
+  // itself using aLoadIdentifier and be kept alive until it completes
+  // loading.
+  return net::DocumentLoadListener::SpeculativeLoadInParent(this, aLoadState);
+}
+
+bool CanonicalBrowsingContext::StartDocumentLoad(
+    net::DocumentLoadListener* aLoad) {
+  // If we're controlling loads from the parent, then starting a new load means
+  // that we need to cancel any existing ones.
+  if (StaticPrefs::browser_tabs_documentchannel_parent_controlled() &&
+      mCurrentLoad) {
+    // Make sure we are not loading a javascript URI.
+    MOZ_ASSERT(!aLoad->IsLoadingJSURI());
+
+    // If we want to do a download, don't cancel the current navigation.
+    if (!aLoad->IsDownload()) {
+      mCurrentLoad->Cancel(NS_BINDING_CANCELLED_OLD_LOAD, ""_ns);
+    }
+  }
+  mCurrentLoad = aLoad;
+
+  if (NS_FAILED(SetCurrentLoadIdentifier(Some(aLoad->GetLoadIdentifier())))) {
+    mCurrentLoad = nullptr;
+    return false;
+  }
+
+  return true;
+}
+
+void CanonicalBrowsingContext::EndDocumentLoad(bool aContinueNavigating) {
+  mCurrentLoad = nullptr;
+
+  if (!aContinueNavigating) {
+    // Resetting the current load identifier on a discarded context
+    // has no effect when a document load has finished.
+    Unused << SetCurrentLoadIdentifier(Nothing());
+  }
+}
+
+already_AddRefed<nsIURI> CanonicalBrowsingContext::GetCurrentURI() const {
+  nsCOMPtr<nsIURI> currentURI;
+  if (nsIDocShell* docShell = GetDocShell()) {
+    MOZ_ALWAYS_SUCCEEDS(
+        nsDocShell::Cast(docShell)->GetCurrentURI(getter_AddRefs(currentURI)));
+  } else {
+    currentURI = mCurrentRemoteURI;
+  }
+  return currentURI.forget();
+}
+
+void CanonicalBrowsingContext::SetCurrentRemoteURI(nsIURI* aCurrentRemoteURI) {
+  MOZ_ASSERT(!GetDocShell());
+  mCurrentRemoteURI = aCurrentRemoteURI;
+}
+
+void CanonicalBrowsingContext::ResetSHEntryHasUserInteractionCache() {
+  WindowContext* topWc = GetTopWindowContext();
+  if (topWc && !topWc->IsDiscarded()) {
+    MOZ_ALWAYS_SUCCEEDS(topWc->SetSHEntryHasUserInteraction(false));
+  }
+}
+
+void CanonicalBrowsingContext::HistoryCommitIndexAndLength() {
+  nsID changeID = {};
+  CallerWillNotifyHistoryIndexAndLengthChanges caller(nullptr);
+  HistoryCommitIndexAndLength(changeID, caller);
+}
+void CanonicalBrowsingContext::HistoryCommitIndexAndLength(
+    const nsID& aChangeID,
+    const CallerWillNotifyHistoryIndexAndLengthChanges& aProofOfCaller) {
+  if (!IsTop()) {
+    Cast(Top())->HistoryCommitIndexAndLength(aChangeID, aProofOfCaller);
+    return;
+  }
+
+  nsISHistory* shistory = GetSessionHistory();
+  if (!shistory) {
+    return;
+  }
+  int32_t index = 0;
+  shistory->GetIndex(&index);
+  int32_t length = shistory->GetCount();
+
+  GetChildSessionHistory()->SetIndexAndLength(index, length, aChangeID);
+
+  shistory->EvictOutOfRangeContentViewers(index);
+
+  Group()->EachParent([&](ContentParent* aParent) {
+    Unused << aParent->SendHistoryCommitIndexAndLength(this, index, length,
+                                                       aChangeID);
+  });
+}
+
+void CanonicalBrowsingContext::SynchronizeLayoutHistoryState() {
+  if (mActiveEntry) {
+    if (IsInProcess()) {
+      nsIDocShell* docShell = GetDocShell();
+      if (docShell) {
+        docShell->PersistLayoutHistoryState();
+
+        nsCOMPtr<nsILayoutHistoryState> state;
+        docShell->GetLayoutHistoryState(getter_AddRefs(state));
+        if (state) {
+          mActiveEntry->SetLayoutHistoryState(state);
+        }
+      }
+    } else if (ContentParent* cp = GetContentParent()) {
+      cp->SendGetLayoutHistoryState(this)->Then(
+          GetCurrentSerialEventTarget(), __func__,
+          [activeEntry = mActiveEntry](
+              const std::tuple<RefPtr<nsILayoutHistoryState>, Maybe<Wireframe>>&
+                  aResult) {
+            if (std::get<0>(aResult)) {
+              activeEntry->SetLayoutHistoryState(std::get<0>(aResult));
+            }
+            if (std::get<1>(aResult)) {
+              activeEntry->SetWireframe(std::get<1>(aResult));
+            }
+          },
+          []() {});
+    }
+  }
+}
+
+void CanonicalBrowsingContext::ResetScalingZoom() {
+  // This currently only ever gets called in the parent process, and we
+  // pass the message on to the WindowGlobalChild for the rootmost browsing
+  // context.
+  if (WindowGlobalParent* topWindow = GetTopWindowContext()) {
+    Unused << topWindow->SendResetScalingZoom();
+  }
+}
+
+void CanonicalBrowsingContext::SetRestoreData(SessionStoreRestoreData* aData,
+                                              ErrorResult& aError) {
+  MOZ_DIAGNOSTIC_ASSERT(aData);
+
+  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(GetParentObject());
+  RefPtr<Promise> promise = Promise::Create(global, aError);
+  if (aError.Failed()) {
+    return;
+  }
+
+  if (NS_WARN_IF(NS_FAILED(SetHasRestoreData(true)))) {
+    aError.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  mRestoreState = new RestoreState();
+  mRestoreState->mData = aData;
+  mRestoreState->mPromise = promise;
+}
+
+already_AddRefed<Promise> CanonicalBrowsingContext::GetRestorePromise() {
+  if (mRestoreState) {
+    return do_AddRef(mRestoreState->mPromise);
+  }
+  return nullptr;
+}
+
+void CanonicalBrowsingContext::ClearRestoreState() {
+  if (!mRestoreState) {
+    MOZ_DIAGNOSTIC_ASSERT(!GetHasRestoreData());
+    return;
+  }
+  if (mRestoreState->mPromise) {
+    mRestoreState->mPromise->MaybeRejectWithUndefined();
+  }
+  mRestoreState = nullptr;
+  MOZ_ALWAYS_SUCCEEDS(SetHasRestoreData(false));
+}
+
+void CanonicalBrowsingContext::RequestRestoreTabContent(
+    WindowGlobalParent* aWindow) {
+  MOZ_DIAGNOSTIC_ASSERT(IsTop());
+
+  if (IsDiscarded() || !mRestoreState || !mRestoreState->mData) {
+    return;
+  }
+
+  CanonicalBrowsingContext* context = aWindow->GetBrowsingContext();
+  MOZ_DIAGNOSTIC_ASSERT(!context->IsDiscarded());
+
+  RefPtr<SessionStoreRestoreData> data =
+      mRestoreState->mData->FindDataForChild(context);
+
+  if (context->IsTop()) {
+    MOZ_DIAGNOSTIC_ASSERT(context == this);
+
+    // We need to wait until the appropriate load event has fired before we
+    // can "complete" the restore process, so if we're holding an empty data
+    // object, just resolve the promise immediately.
+    if (mRestoreState->mData->IsEmpty()) {
+      MOZ_DIAGNOSTIC_ASSERT(!data || data->IsEmpty());
+      mRestoreState->Resolve();
+      ClearRestoreState();
+      return;
+    }
+
+    // Since we're following load event order, we'll only arrive here for a
+    // toplevel context after we've already sent down data for all child frames,
+    // so it's safe to clear this reference now. The completion callback below
+    // relies on the mData field being null to determine if all requests have
+    // been sent out.
+    mRestoreState->ClearData();
+    MOZ_ALWAYS_SUCCEEDS(SetHasRestoreData(false));
+  }
+
+  if (data && !data->IsEmpty()) {
+    auto onTabRestoreComplete = [self = RefPtr{this},
+                                 state = RefPtr{mRestoreState}](auto) {
+      state->mResolves++;
+      if (!state->mData && state->mRequests == state->mResolves) {
+        state->Resolve();
+        if (state == self->mRestoreState) {
+          self->ClearRestoreState();
+        }
+      }
+    };
+
+    mRestoreState->mRequests++;
+
+    if (data->CanRestoreInto(aWindow->GetDocumentURI())) {
+      if (!aWindow->IsInProcess()) {
+        aWindow->SendRestoreTabContent(WrapNotNull(data.get()),
+                                       onTabRestoreComplete,
+                                       onTabRestoreComplete);
+        return;
+      }
+      data->RestoreInto(context);
+    }
+
+    // This must be called both when we're doing an in-process restore, and when
+    // we didn't do a restore at all due to a URL mismatch.
+    onTabRestoreComplete(true);
+  }
+}
+
+void CanonicalBrowsingContext::RestoreState::Resolve() {
+  MOZ_DIAGNOSTIC_ASSERT(mPromise);
+  mPromise->MaybeResolveWithUndefined();
+  mPromise = nullptr;
+}
+
+nsresult CanonicalBrowsingContext::WriteSessionStorageToSessionStore(
+    const nsTArray<SSCacheCopy>& aSesssionStorage, uint32_t aEpoch) {
+  nsCOMPtr<nsISessionStoreFunctions> funcs = do_ImportESModule(
+      "resource://gre/modules/SessionStoreFunctions.sys.mjs", fallible);
+  if (!funcs) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIXPConnectWrappedJS> wrapped = do_QueryInterface(funcs);
+  AutoJSAPI jsapi;
+  if (!jsapi.Init(wrapped->GetJSObjectGlobal())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  JS::Rooted<JS::Value> key(jsapi.cx(), Top()->PermanentKey());
+
+  Record<nsCString, Record<nsString, nsString>> storage;
+  JS::Rooted<JS::Value> update(jsapi.cx());
+
+  if (!aSesssionStorage.IsEmpty()) {
+    SessionStoreUtils::ConstructSessionStorageValues(this, aSesssionStorage,
+                                                     storage);
+    if (!ToJSValue(jsapi.cx(), storage, &update)) {
+      return NS_ERROR_FAILURE;
+    }
+  } else {
+    update.setNull();
+  }
+
+  return funcs->UpdateSessionStoreForStorage(Top()->GetEmbedderElement(), this,
+                                             key, aEpoch, update);
+}
+
+void CanonicalBrowsingContext::UpdateSessionStoreSessionStorage(
+    const std::function<void()>& aDone) {
+  if (!StaticPrefs::browser_sessionstore_collect_session_storage_AtStartup()) {
+    aDone();
+    return;
+  }
+
+  using DataPromise = BackgroundSessionStorageManager::DataPromise;
+  BackgroundSessionStorageManager::GetData(
+      this, StaticPrefs::browser_sessionstore_dom_storage_limit(),
+      /* aClearSessionStoreTimer = */ true)
+      ->Then(GetCurrentSerialEventTarget(), __func__,
+             [self = RefPtr{this}, aDone, epoch = GetSessionStoreEpoch()](
+                 const DataPromise::ResolveOrRejectValue& valueList) {
+               if (valueList.IsResolve()) {
+                 self->WriteSessionStorageToSessionStore(
+                     valueList.ResolveValue(), epoch);
+               }
+               aDone();
+             });
+}
+
+/* static */
+void CanonicalBrowsingContext::UpdateSessionStoreForStorage(
+    uint64_t aBrowsingContextId) {
+  RefPtr<CanonicalBrowsingContext> browsingContext = Get(aBrowsingContextId);
+
+  if (!browsingContext) {
+    return;
+  }
+
+  browsingContext->UpdateSessionStoreSessionStorage([]() {});
+}
+
+void CanonicalBrowsingContext::MaybeScheduleSessionStoreUpdate() {
+  if (!StaticPrefs::browser_sessionstore_platform_collection_AtStartup()) {
+    return;
+  }
+
+  if (!IsTop()) {
+    Top()->MaybeScheduleSessionStoreUpdate();
+    return;
+  }
+
+  if (IsInBFCache()) {
+    return;
+  }
+
+  if (mSessionStoreSessionStorageUpdateTimer) {
+    return;
+  }
+
+  if (!StaticPrefs::browser_sessionstore_debug_no_auto_updates()) {
+    auto result = NS_NewTimerWithFuncCallback(
+        [](nsITimer*, void* aClosure) {
+          auto* context = static_cast<CanonicalBrowsingContext*>(aClosure);
+          context->UpdateSessionStoreSessionStorage([]() {});
+        },
+        this, StaticPrefs::browser_sessionstore_interval(),
+        nsITimer::TYPE_ONE_SHOT,
+        "CanonicalBrowsingContext::MaybeScheduleSessionStoreUpdate");
+
+    if (result.isErr()) {
+      return;
+    }
+
+    mSessionStoreSessionStorageUpdateTimer = result.unwrap();
+  }
+}
+
+void CanonicalBrowsingContext::CancelSessionStoreUpdate() {
+  if (mSessionStoreSessionStorageUpdateTimer) {
+    mSessionStoreSessionStorageUpdateTimer->Cancel();
+    mSessionStoreSessionStorageUpdateTimer = nullptr;
+  }
+}
+
+void CanonicalBrowsingContext::SetContainerFeaturePolicy(
+    FeaturePolicy* aContainerFeaturePolicy) {
+  mContainerFeaturePolicy = aContainerFeaturePolicy;
+
+  if (WindowGlobalParent* current = GetCurrentWindowGlobal()) {
+    Unused << current->SendSetContainerFeaturePolicy(mContainerFeaturePolicy);
+  }
+}
+
+void CanonicalBrowsingContext::SetCrossGroupOpenerId(uint64_t aOpenerId) {
+  MOZ_DIAGNOSTIC_ASSERT(IsTopContent());
+  MOZ_DIAGNOSTIC_ASSERT(mCrossGroupOpenerId == 0,
+                        "Can only set CrossGroupOpenerId once");
+  mCrossGroupOpenerId = aOpenerId;
+}
+
+void CanonicalBrowsingContext::SetCrossGroupOpener(
+    CanonicalBrowsingContext& aCrossGroupOpener, ErrorResult& aRv) {
+  if (!IsTopContent()) {
+    aRv.ThrowNotAllowedError(
+        "Can only set crossGroupOpener on toplevel content");
+    return;
+  }
+  if (mCrossGroupOpenerId != 0) {
+    aRv.ThrowNotAllowedError("Can only set crossGroupOpener once");
+    return;
+  }
+
+  SetCrossGroupOpenerId(aCrossGroupOpener.Id());
+}
+
+auto CanonicalBrowsingContext::FindUnloadingHost(uint64_t aChildID)
+    -> nsTArray<UnloadingHost>::iterator {
+  return std::find_if(
+      mUnloadingHosts.begin(), mUnloadingHosts.end(),
+      [&](const auto& host) { return host.mChildID == aChildID; });
+}
+
+void CanonicalBrowsingContext::ClearUnloadingHost(uint64_t aChildID) {
+  // Notify any callbacks which were waiting for the host to finish unloading
+  // that it has.
+  auto found = FindUnloadingHost(aChildID);
+  if (found != mUnloadingHosts.end()) {
+    auto callbacks = std::move(found->mCallbacks);
+    mUnloadingHosts.RemoveElementAt(found);
+    for (const auto& callback : callbacks) {
+      callback();
+    }
+  }
+}
+
+void CanonicalBrowsingContext::StartUnloadingHost(uint64_t aChildID) {
+  MOZ_DIAGNOSTIC_ASSERT(FindUnloadingHost(aChildID) == mUnloadingHosts.end());
+  mUnloadingHosts.AppendElement(UnloadingHost{aChildID, {}});
+}
+
+void CanonicalBrowsingContext::BrowserParentDestroyed(
+    BrowserParent* aBrowserParent, bool aAbnormalShutdown) {
+  ClearUnloadingHost(aBrowserParent->Manager()->ChildID());
+
+  // Handling specific to when the current BrowserParent has been destroyed.
+  if (mCurrentBrowserParent == aBrowserParent) {
+    mCurrentBrowserParent = nullptr;
+
+    // If this BrowserParent is for a subframe, attempt to recover from a
+    // subframe crash by rendering the subframe crashed page in the embedding
+    // content.
+    if (aAbnormalShutdown) {
+      ShowSubframeCrashedUI(aBrowserParent->GetBrowserBridgeParent());
+    }
+  }
+}
+
+void CanonicalBrowsingContext::ShowSubframeCrashedUI(
+    BrowserBridgeParent* aBridge) {
+  if (!aBridge || IsDiscarded() || !aBridge->CanSend()) {
+    return;
+  }
+
+  MOZ_DIAGNOSTIC_ASSERT(!aBridge->GetBrowsingContext() ||
+                        aBridge->GetBrowsingContext() == this);
+
+  // There is no longer a current inner window within this
+  // BrowsingContext, update the `CurrentInnerWindowId` field to reflect
+  // this.
+  MOZ_ALWAYS_SUCCEEDS(SetCurrentInnerWindowId(0));
+
+  // The owning process will now be the embedder to render the subframe
+  // crashed page, switch ownership back over.
+  SetOwnerProcessId(aBridge->Manager()->Manager()->ChildID());
+  SetCurrentBrowserParent(aBridge->Manager());
+
+  Unused << aBridge->SendSubFrameCrashed();
+}
+
+static void LogBFCacheBlockingForDoc(BrowsingContext* aBrowsingContext,
+                                     uint32_t aBFCacheCombo, bool aIsSubDoc) {
+  if (aIsSubDoc) {
+    nsAutoCString uri("[no uri]");
+    nsCOMPtr<nsIURI> currentURI =
+        aBrowsingContext->Canonical()->GetCurrentURI();
+    if (currentURI) {
+      uri = currentURI->GetSpecOrDefault();
+    }
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug,
+            (" ** Blocked for document %s", uri.get()));
+  }
+  if (aBFCacheCombo & BFCacheStatus::EVENT_HANDLING_SUPPRESSED) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug,
+            (" * event handling suppression"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::SUSPENDED) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * suspended Window"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::UNLOAD_LISTENER) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * unload listener"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::REQUEST) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * requests in the loadgroup"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::ACTIVE_GET_USER_MEDIA) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * GetUserMedia"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::ACTIVE_PEER_CONNECTION) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * PeerConnection"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::CONTAINS_EME_CONTENT) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * EME content"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::CONTAINS_MSE_CONTENT) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * MSE use"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::HAS_ACTIVE_SPEECH_SYNTHESIS) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * Speech use"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::HAS_USED_VR) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * used VR"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::BEFOREUNLOAD_LISTENER) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * beforeunload listener"));
+  }
+  if (aBFCacheCombo & BFCacheStatus::ACTIVE_LOCK) {
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * has active Web Locks"));
+  }
+}
+
+bool CanonicalBrowsingContext::AllowedInBFCache(
+    const Maybe<uint64_t>& aChannelId, nsIURI* aNewURI) {
+  if (MOZ_UNLIKELY(MOZ_LOG_TEST(gSHIPBFCacheLog, LogLevel::Debug))) {
+    nsAutoCString uri("[no uri]");
+    nsCOMPtr<nsIURI> currentURI = GetCurrentURI();
+    if (currentURI) {
+      uri = currentURI->GetSpecOrDefault();
+    }
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, ("Checking %s", uri.get()));
+  }
+
+  if (IsInProcess()) {
+    return false;
+  }
+
+  uint32_t bfcacheCombo = 0;
+  if (mRestoreState) {
+    bfcacheCombo |= BFCacheStatus::RESTORING;
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * during session restore"));
+  }
+
+  if (Group()->Toplevels().Length() > 1) {
+    bfcacheCombo |= BFCacheStatus::NOT_ONLY_TOPLEVEL_IN_BCG;
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug,
+            (" * auxiliary BrowsingContexts"));
+  }
+
+  // There are not a lot of about:* pages that are allowed to load in
+  // subframes, so it's OK to allow those few about:* pages enter BFCache.
+  MOZ_ASSERT(IsTop(), "Trying to put a non top level BC into BFCache");
+
+  WindowGlobalParent* wgp = GetCurrentWindowGlobal();
+  if (wgp && wgp->GetDocumentURI()) {
+    nsCOMPtr<nsIURI> currentURI = wgp->GetDocumentURI();
+    // Exempt about:* pages from bfcache, with the exception of about:blank
+    if (currentURI->SchemeIs("about") &&
+        !currentURI->GetSpecOrDefault().EqualsLiteral("about:blank")) {
+      bfcacheCombo |= BFCacheStatus::ABOUT_PAGE;
+      MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug, (" * about:* page"));
+    }
+
+    if (aNewURI) {
+      bool equalUri = false;
+      aNewURI->Equals(currentURI, &equalUri);
+      if (equalUri) {
+        // When loading the same uri, disable bfcache so that
+        // nsDocShell::OnNewURI transforms the load to LOAD_NORMAL_REPLACE.
+        return false;
+      }
+    }
+  }
+
+  // For telemetry we're collecting all the flags for all the BCs hanging
+  // from this top-level BC.
+  PreOrderWalk([&](BrowsingContext* aBrowsingContext) {
+    WindowGlobalParent* wgp =
+        aBrowsingContext->Canonical()->GetCurrentWindowGlobal();
+    uint32_t subDocBFCacheCombo = wgp ? wgp->GetBFCacheStatus() : 0;
+    if (wgp) {
+      const Maybe<uint64_t>& singleChannelId = wgp->GetSingleChannelId();
+      if (singleChannelId.isSome()) {
+        if (singleChannelId.value() == 0 || aChannelId.isNothing() ||
+            singleChannelId.value() != aChannelId.value()) {
+          subDocBFCacheCombo |= BFCacheStatus::REQUEST;
+        }
+      }
+    }
+
+    if (MOZ_UNLIKELY(MOZ_LOG_TEST(gSHIPBFCacheLog, LogLevel::Debug))) {
+      LogBFCacheBlockingForDoc(aBrowsingContext, subDocBFCacheCombo,
+                               aBrowsingContext != this);
+    }
+
+    bfcacheCombo |= subDocBFCacheCombo;
+  });
+
+  nsDocShell::ReportBFCacheComboTelemetry(bfcacheCombo);
+  if (MOZ_UNLIKELY(MOZ_LOG_TEST(gSHIPBFCacheLog, LogLevel::Debug))) {
+    nsAutoCString uri("[no uri]");
+    nsCOMPtr<nsIURI> currentURI = GetCurrentURI();
+    if (currentURI) {
+      uri = currentURI->GetSpecOrDefault();
+    }
+    MOZ_LOG(gSHIPBFCacheLog, LogLevel::Debug,
+            (" +> %s %s be blocked from going into the BFCache", uri.get(),
+             bfcacheCombo == 0 ? "shouldn't" : "should"));
+  }
+
+  if (StaticPrefs::docshell_shistory_bfcache_allow_unload_listeners()) {
+    bfcacheCombo &= ~BFCacheStatus::UNLOAD_LISTENER;
+  }
+
+  return bfcacheCombo == 0;
+}
+
+void CanonicalBrowsingContext::SetTouchEventsOverride(
+    dom::TouchEventsOverride aOverride, ErrorResult& aRv) {
+  SetTouchEventsOverrideInternal(aOverride, aRv);
+}
+
+void CanonicalBrowsingContext::SetTargetTopLevelLinkClicksToBlank(
+    bool aTargetTopLevelLinkClicksToBlank, ErrorResult& aRv) {
+  SetTargetTopLevelLinkClicksToBlankInternal(aTargetTopLevelLinkClicksToBlank,
+                                             aRv);
+}
+
+void CanonicalBrowsingContext::AddPageAwakeRequest() {
+  MOZ_ASSERT(IsTop());
+  auto count = GetPageAwakeRequestCount();
+  MOZ_ASSERT(count < UINT32_MAX);
+  Unused << SetPageAwakeRequestCount(++count);
+}
+
+void CanonicalBrowsingContext::RemovePageAwakeRequest() {
+  MOZ_ASSERT(IsTop());
+  auto count = GetPageAwakeRequestCount();
+  MOZ_ASSERT(count > 0);
+  Unused << SetPageAwakeRequestCount(--count);
+}
+
+void CanonicalBrowsingContext::CloneDocumentTreeInto(
+    CanonicalBrowsingContext* aSource, const nsACString& aRemoteType,
+    embedding::PrintData&& aPrintData) {
+  NavigationIsolationOptions options;
+  options.mRemoteType = aRemoteType;
+
+  mClonePromise =
+      ChangeRemoteness(options, /* aPendingSwitchId = */ 0)
+          ->Then(
+              GetMainThreadSerialEventTarget(), __func__,
+              [source = MaybeDiscardedBrowsingContext{aSource},
+               data = std::move(aPrintData)](
+                  BrowserParent* aBp) -> RefPtr<GenericNonExclusivePromise> {
+                RefPtr<BrowserBridgeParent> bridge =
+                    aBp->GetBrowserBridgeParent();
+                return aBp->SendCloneDocumentTreeIntoSelf(source, data)
+                    ->Then(
+                        GetMainThreadSerialEventTarget(), __func__,
+                        [bridge](
+                            BrowserParent::CloneDocumentTreeIntoSelfPromise::
+                                ResolveOrRejectValue&& aValue) {
+                          // We're cloning a remote iframe, so we created a
+                          // BrowserBridge which makes us register an OOP load
+                          // (see Document::OOPChildLoadStarted), even though
+                          // this isn't a real load. We call
+                          // SendMaybeFireEmbedderLoadEvents here so that we do
+                          // register the end of the load (see
+                          // Document::OOPChildLoadDone).
+                          if (bridge) {
+                            Unused << bridge->SendMaybeFireEmbedderLoadEvents(
+                                EmbedderElementEventType::NoEvent);
+                          }
+                          if (aValue.IsResolve() && aValue.ResolveValue()) {
+                            return GenericNonExclusivePromise::CreateAndResolve(
+                                true, __func__);
+                          }
+                          return GenericNonExclusivePromise::CreateAndReject(
+                              NS_ERROR_FAILURE, __func__);
+                        });
+              },
+              [](nsresult aRv) -> RefPtr<GenericNonExclusivePromise> {
+                NS_WARNING(
+                    nsPrintfCString("Remote clone failed: %x\n", unsigned(aRv))
+                        .get());
+                return GenericNonExclusivePromise::CreateAndReject(
+                    NS_ERROR_FAILURE, __func__);
+              });
+
+  mClonePromise->Then(
+      GetMainThreadSerialEventTarget(), __func__,
+      [self = RefPtr{this}]() { self->mClonePromise = nullptr; });
+}
+
+bool CanonicalBrowsingContext::StartApzAutoscroll(float aAnchorX,
+                                                  float aAnchorY,
+                                                  nsViewID aScrollId,
+                                                  uint32_t aPresShellId) {
+  nsCOMPtr<nsIWidget> widget;
+  mozilla::layers::LayersId layersId{0};
+
+  if (IsInProcess()) {
+    nsCOMPtr<nsPIDOMWindowOuter> outer = GetDOMWindow();
+    if (!outer) {
+      return false;
+    }
+
+    widget = widget::WidgetUtils::DOMWindowToWidget(outer);
+    if (widget) {
+      layersId = widget->GetRootLayerTreeId();
+    }
+  } else {
+    RefPtr<BrowserParent> parent = GetBrowserParent();
+    if (!parent) {
+      return false;
+    }
+
+    widget = parent->GetWidget();
+    layersId = parent->GetLayersId();
+  }
+
+  if (!widget || !widget->AsyncPanZoomEnabled()) {
+    return false;
+  }
+
+  // The anchor coordinates that are passed in are relative to the origin of the
+  // screen, but we are sending them to APZ which only knows about coordinates
+  // relative to the widget, so convert them accordingly.
+  const LayoutDeviceIntPoint anchor =
+      RoundedToInt(LayoutDevicePoint(aAnchorX, aAnchorY)) -
+      widget->WidgetToScreenOffset();
+
+  mozilla::layers::ScrollableLayerGuid guid(layersId, aPresShellId, aScrollId);
+
+  return widget->StartAsyncAutoscroll(
+      ViewAs<ScreenPixel>(
+          anchor, PixelCastJustification::LayoutDeviceIsScreenForBounds),
+      guid);
+}
+
+void CanonicalBrowsingContext::StopApzAutoscroll(nsViewID aScrollId,
+                                                 uint32_t aPresShellId) {
+  nsCOMPtr<nsIWidget> widget;
+  mozilla::layers::LayersId layersId{0};
+
+  if (IsInProcess()) {
+    nsCOMPtr<nsPIDOMWindowOuter> outer = GetDOMWindow();
+    if (!outer) {
+      return;
+    }
+
+    widget = widget::WidgetUtils::DOMWindowToWidget(outer);
+    if (widget) {
+      layersId = widget->GetRootLayerTreeId();
+    }
+  } else {
+    RefPtr<BrowserParent> parent = GetBrowserParent();
+    if (!parent) {
+      return;
+    }
+
+    widget = parent->GetWidget();
+    layersId = parent->GetLayersId();
+  }
+
+  if (!widget || !widget->AsyncPanZoomEnabled()) {
+    return;
+  }
+
+  mozilla::layers::ScrollableLayerGuid guid(layersId, aPresShellId, aScrollId);
+  widget->StopAsyncAutoscroll(guid);
+}
+
+already_AddRefed<nsISHEntry>
+CanonicalBrowsingContext::GetMostRecentLoadingSessionHistoryEntry() {
+  if (mLoadingEntries.IsEmpty()) {
+    return nullptr;
+  }
+
+  RefPtr<SessionHistoryEntry> entry = mLoadingEntries.LastElement().mEntry;
+  return entry.forget();
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(CanonicalBrowsingContext)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(CanonicalBrowsingContext,
+                                                BrowsingContext)
+  tmp->mPermanentKey.setNull();
+  if (tmp->mSessionHistory) {
+    tmp->mSessionHistory->SetBrowsingContext(nullptr);
+  }
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mSessionHistory, mContainerFeaturePolicy,
+                                  mCurrentBrowserParent, mWebProgress,
+                                  mSessionStoreSessionStorageUpdateTimer)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(CanonicalBrowsingContext,
+                                                  BrowsingContext)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSessionHistory, mContainerFeaturePolicy,
+                                    mCurrentBrowserParent, mWebProgress,
+                                    mSessionStoreSessionStorageUpdateTimer)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(CanonicalBrowsingContext,
+                                               BrowsingContext)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mPermanentKey)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+NS_IMPL_ADDREF_INHERITED(CanonicalBrowsingContext, BrowsingContext)
+NS_IMPL_RELEASE_INHERITED(CanonicalBrowsingContext, BrowsingContext)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CanonicalBrowsingContext)
+NS_INTERFACE_MAP_END_INHERITING(BrowsingContext)
+
+}  // namespace dom
+}  // namespace mozilla