Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 2548 insertions, 0 deletions

diff --git a/toolkit/components/windowwatcher/nsWindowWatcher.cpp b/toolkit/components/windowwatcher/nsWindowWatcher.cpp
new file mode 100644
index 0000000000..209af157a3
--- /dev/null
+++ b/toolkit/components/windowwatcher/nsWindowWatcher.cpp
@@ -0,0 +1,2548 @@
+/* -*- 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 "nsWindowWatcher.h"
+#include "nsAutoWindowStateHelper.h"
+
+#include "nsCRT.h"
+#include "nsDebug.h"
+#include "nsNetUtil.h"
+#include "nsIAuthPrompt.h"
+#include "nsIAuthPrompt2.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsJSUtils.h"
+
+#include "nsDocShell.h"
+#include "nsGlobalWindowInner.h"
+#include "nsGlobalWindowOuter.h"
+#include "nsHashPropertyBag.h"
+#include "nsIBaseWindow.h"
+#include "nsIBrowserDOMWindow.h"
+#include "nsIDocShell.h"
+#include "nsDocShellLoadState.h"
+#include "nsIDocShellTreeItem.h"
+#include "nsIDocShellTreeOwner.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/BrowsingContextGroup.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "mozilla/dom/UserActivation.h"
+#include "nsIDragService.h"
+#include "nsIPrompt.h"
+#include "nsIScriptObjectPrincipal.h"
+#include "nsIScreen.h"
+#include "nsIScreenManager.h"
+#include "nsIScriptContext.h"
+#include "nsIObserverService.h"
+#include "nsXPCOM.h"
+#include "nsIURI.h"
+#include "nsIWebBrowser.h"
+#include "nsIWebBrowserChrome.h"
+#include "nsIWebNavigation.h"
+#include "nsIWindowCreator.h"
+#include "nsIXULRuntime.h"
+#include "nsPIDOMWindow.h"
+#include "nsIWindowProvider.h"
+#include "nsIMutableArray.h"
+#include "nsIDOMStorageManager.h"
+#include "nsIWidget.h"
+#include "nsFocusManager.h"
+#include "nsOpenWindowInfo.h"
+#include "nsPresContext.h"
+#include "nsContentUtils.h"
+#include "nsIPrefBranch.h"
+#include "nsIPrefService.h"
+#include "nsSandboxFlags.h"
+#include "nsSimpleEnumerator.h"
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/NullPrincipal.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ResultExtensions.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/StaticPrefs_full_screen_api.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/Storage.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/dom/BrowserParent.h"
+#include "mozilla/dom/BrowserHost.h"
+#include "mozilla/dom/DocGroup.h"
+#include "mozilla/dom/WindowGlobalChild.h"
+#include "mozilla/dom/SessionStorageManager.h"
+#include "nsIAppWindow.h"
+#include "nsIXULBrowserWindow.h"
+#include "ReferrerInfo.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+/****************************************************************
+ ******************** nsWatcherWindowEntry **********************
+ ****************************************************************/
+
+class nsWindowWatcher;
+
+struct nsWatcherWindowEntry {
+  nsWatcherWindowEntry(mozIDOMWindowProxy* aWindow,
+                       nsIWebBrowserChrome* aChrome)
+      : mChrome(nullptr) {
+    mWindow = aWindow;
+    nsCOMPtr<nsISupportsWeakReference> supportsweak(do_QueryInterface(aChrome));
+    if (supportsweak) {
+      supportsweak->GetWeakReference(getter_AddRefs(mChromeWeak));
+    } else {
+      mChrome = aChrome;
+      mChromeWeak = nullptr;
+    }
+    ReferenceSelf();
+  }
+  ~nsWatcherWindowEntry() = default;
+
+  void InsertAfter(nsWatcherWindowEntry* aOlder);
+  void Unlink();
+  void ReferenceSelf();
+
+  mozIDOMWindowProxy* mWindow;
+  nsIWebBrowserChrome* mChrome;
+  nsWeakPtr mChromeWeak;
+  // each struct is in a circular, doubly-linked list
+  nsWatcherWindowEntry* mYounger;  // next younger in sequence
+  nsWatcherWindowEntry* mOlder;
+};
+
+void nsWatcherWindowEntry::InsertAfter(nsWatcherWindowEntry* aOlder) {
+  if (aOlder) {
+    mOlder = aOlder;
+    mYounger = aOlder->mYounger;
+    mOlder->mYounger = this;
+    if (mOlder->mOlder == mOlder) {
+      mOlder->mOlder = this;
+    }
+    mYounger->mOlder = this;
+    if (mYounger->mYounger == mYounger) {
+      mYounger->mYounger = this;
+    }
+  }
+}
+
+void nsWatcherWindowEntry::Unlink() {
+  mOlder->mYounger = mYounger;
+  mYounger->mOlder = mOlder;
+  ReferenceSelf();
+}
+
+void nsWatcherWindowEntry::ReferenceSelf() {
+  mYounger = this;
+  mOlder = this;
+}
+
+/****************************************************************
+ ****************** nsWatcherWindowEnumerator *******************
+ ****************************************************************/
+
+class nsWatcherWindowEnumerator : public nsSimpleEnumerator {
+ public:
+  explicit nsWatcherWindowEnumerator(nsWindowWatcher* aWatcher);
+  NS_IMETHOD HasMoreElements(bool* aResult) override;
+  NS_IMETHOD GetNext(nsISupports** aResult) override;
+
+ protected:
+  ~nsWatcherWindowEnumerator() override;
+
+ private:
+  friend class nsWindowWatcher;
+
+  nsWatcherWindowEntry* FindNext();
+  void WindowRemoved(nsWatcherWindowEntry* aInfo);
+
+  nsWindowWatcher* mWindowWatcher;
+  nsWatcherWindowEntry* mCurrentPosition;
+};
+
+nsWatcherWindowEnumerator::nsWatcherWindowEnumerator(nsWindowWatcher* aWatcher)
+    : mWindowWatcher(aWatcher), mCurrentPosition(aWatcher->mOldestWindow) {
+  mWindowWatcher->AddEnumerator(this);
+  mWindowWatcher->AddRef();
+}
+
+nsWatcherWindowEnumerator::~nsWatcherWindowEnumerator() {
+  mWindowWatcher->RemoveEnumerator(this);
+  mWindowWatcher->Release();
+}
+
+NS_IMETHODIMP
+nsWatcherWindowEnumerator::HasMoreElements(bool* aResult) {
+  if (!aResult) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  *aResult = !!mCurrentPosition;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWatcherWindowEnumerator::GetNext(nsISupports** aResult) {
+  if (!aResult) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  *aResult = nullptr;
+
+  if (mCurrentPosition) {
+    CallQueryInterface(mCurrentPosition->mWindow, aResult);
+    mCurrentPosition = FindNext();
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
+
+nsWatcherWindowEntry* nsWatcherWindowEnumerator::FindNext() {
+  nsWatcherWindowEntry* info;
+
+  if (!mCurrentPosition) {
+    return nullptr;
+  }
+
+  info = mCurrentPosition->mYounger;
+  return info == mWindowWatcher->mOldestWindow ? nullptr : info;
+}
+
+// if a window is being removed adjust the iterator's current position
+void nsWatcherWindowEnumerator::WindowRemoved(nsWatcherWindowEntry* aInfo) {
+  if (mCurrentPosition == aInfo) {
+    mCurrentPosition =
+        mCurrentPosition != aInfo->mYounger ? aInfo->mYounger : nullptr;
+  }
+}
+
+/****************************************************************
+ *********************** nsWindowWatcher ************************
+ ****************************************************************/
+
+NS_IMPL_ADDREF(nsWindowWatcher)
+NS_IMPL_RELEASE(nsWindowWatcher)
+NS_IMPL_QUERY_INTERFACE(nsWindowWatcher, nsIWindowWatcher, nsIPromptFactory,
+                        nsPIWindowWatcher)
+
+nsWindowWatcher::nsWindowWatcher()
+    : mOldestWindow(nullptr), mListLock("nsWindowWatcher.mListLock") {}
+
+nsWindowWatcher::~nsWindowWatcher() {
+  // delete data
+  while (mOldestWindow) {
+    RemoveWindow(mOldestWindow);
+  }
+}
+
+nsresult nsWindowWatcher::Init() { return NS_OK; }
+
+/**
+ * Convert aArguments into either an nsIArray or nullptr.
+ *
+ *  - If aArguments is nullptr, return nullptr.
+ *  - If aArguments is an nsArray, return nullptr if it's empty, or otherwise
+ *    return the array.
+ *  - If aArguments is an nsIArray, return nullptr if it's empty, or
+ *    otherwise just return the array.
+ *  - Otherwise, return an nsIArray with one element: aArguments.
+ */
+static already_AddRefed<nsIArray> ConvertArgsToArray(nsISupports* aArguments) {
+  if (!aArguments) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIArray> array = do_QueryInterface(aArguments);
+  if (array) {
+    uint32_t argc = 0;
+    array->GetLength(&argc);
+    if (argc == 0) {
+      return nullptr;
+    }
+
+    return array.forget();
+  }
+
+  nsCOMPtr<nsIMutableArray> singletonArray =
+      do_CreateInstance(NS_ARRAY_CONTRACTID);
+  NS_ENSURE_TRUE(singletonArray, nullptr);
+
+  nsresult rv = singletonArray->AppendElement(aArguments);
+  NS_ENSURE_SUCCESS(rv, nullptr);
+
+  return singletonArray.forget();
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::OpenWindow(mozIDOMWindowProxy* aParent, const nsACString& aUrl,
+                            const nsACString& aName,
+                            const nsACString& aFeatures,
+                            nsISupports* aArguments,
+                            mozIDOMWindowProxy** aResult) {
+  nsCOMPtr<nsIArray> argv = ConvertArgsToArray(aArguments);
+
+  uint32_t argc = 0;
+  if (argv) {
+    argv->GetLength(&argc);
+  }
+  bool dialog = (argc != 0);
+
+  RefPtr<BrowsingContext> bc;
+  MOZ_TRY(OpenWindowInternal(aParent, aUrl, aName, aFeatures,
+                             mozilla::dom::UserActivation::Modifiers::None(),
+                             /* calledFromJS = */ false, dialog,
+                             /* navigate = */ true, argv,
+                             /* aIsPopupSpam = */ false,
+                             /* aForceNoOpener = */ false,
+                             /* aForceNoReferrer = */ false, PRINT_NONE,
+                             /* aLoadState = */ nullptr, getter_AddRefs(bc)));
+  if (bc) {
+    nsCOMPtr<mozIDOMWindowProxy> win(bc->GetDOMWindow());
+    win.forget(aResult);
+  }
+  return NS_OK;
+}
+
+struct SizeSpec {
+  SizeSpec() = default;
+
+  // We store these in screen-independent pixels.
+  Maybe<DesktopIntCoord> mLeft;
+  Maybe<DesktopIntCoord> mTop;
+  Maybe<CSSIntCoord> mOuterWidth;   // Total window width
+  Maybe<CSSIntCoord> mOuterHeight;  // Total window height
+  Maybe<CSSIntCoord> mInnerWidth;   // Content area width
+  Maybe<CSSIntCoord> mInnerHeight;  // Content area height
+
+  bool mLockAspectRatio = false;
+
+  bool PositionSpecified() const { return mLeft.isSome() || mTop.isSome(); }
+
+  bool SizeSpecified() const { return WidthSpecified() || HeightSpecified(); }
+
+  bool WidthSpecified() const {
+    return mOuterWidth.isSome() || mInnerWidth.isSome();
+  }
+
+  bool HeightSpecified() const {
+    return mOuterHeight.isSome() || mInnerHeight.isSome();
+  }
+
+  void ScaleBy(float aOpenerZoom) {
+    if (aOpenerZoom == 1.0f) {
+      return;
+    }
+    auto Scale = [&aOpenerZoom](auto& aValue) {
+      if (aValue) {
+        *aValue = NSToIntRound(*aValue * aOpenerZoom);
+      }
+    };
+    // Scaling the position is needed to make sure that the window position is
+    // what the caller expects.
+    Scale(mLeft);
+    Scale(mTop);
+
+    // Scaling these CSS sizes by the zoom factor might be a bit dubious, as the
+    // created window should not be zoomed, but we've done that historically...
+    Scale(mOuterWidth);
+    Scale(mOuterHeight);
+    Scale(mInnerWidth);
+    Scale(mInnerHeight);
+  }
+};
+
+static void SizeOpenedWindow(nsIDocShellTreeOwner* aTreeOwner,
+                             mozIDOMWindowProxy* aParent, bool aIsCallerChrome,
+                             const SizeSpec&);
+static SizeSpec CalcSizeSpec(const WindowFeatures&, bool aHasChromeParent,
+                             CSSToDesktopScale);
+
+NS_IMETHODIMP
+nsWindowWatcher::OpenWindow2(
+    mozIDOMWindowProxy* aParent, const nsACString& aUrl,
+    const nsACString& aName, const nsACString& aFeatures,
+    const UserActivation::Modifiers& aModifiers, bool aCalledFromScript,
+    bool aDialog, bool aNavigate, nsISupports* aArguments, bool aIsPopupSpam,
+    bool aForceNoOpener, bool aForceNoReferrer, PrintKind aPrintKind,
+    nsDocShellLoadState* aLoadState, BrowsingContext** aResult) {
+  nsCOMPtr<nsIArray> argv = ConvertArgsToArray(aArguments);
+
+  uint32_t argc = 0;
+  if (argv) {
+    argv->GetLength(&argc);
+  }
+
+  // This is extremely messed up, but this behavior is necessary because
+  // callers lie about whether they're a dialog window and whether they're
+  // called from script.  Fixing this is bug 779939.
+  bool dialog = aDialog;
+  if (!aCalledFromScript) {
+    dialog = argc > 0;
+  }
+
+  return OpenWindowInternal(aParent, aUrl, aName, aFeatures, aModifiers,
+                            aCalledFromScript, dialog, aNavigate, argv,
+                            aIsPopupSpam, aForceNoOpener, aForceNoReferrer,
+                            aPrintKind, aLoadState, aResult);
+}
+
+// This static function checks if the aDocShell uses an UserContextId equal to
+// the userContextId of subjectPrincipal, if not null.
+static bool CheckUserContextCompatibility(nsIDocShell* aDocShell) {
+  MOZ_ASSERT(aDocShell);
+
+  uint32_t userContextId =
+      static_cast<nsDocShell*>(aDocShell)->GetOriginAttributes().mUserContextId;
+
+  nsCOMPtr<nsIPrincipal> subjectPrincipal =
+      nsContentUtils::GetCurrentJSContext() ? nsContentUtils::SubjectPrincipal()
+                                            : nullptr;
+
+  // If we don't have a valid principal, probably we are in e10s mode, parent
+  // side.
+  if (!subjectPrincipal) {
+    return true;
+  }
+
+  // DocShell can have UsercontextID set but loading a document with system
+  // principal. In this case, we consider everything ok.
+  if (subjectPrincipal->IsSystemPrincipal()) {
+    return true;
+  }
+
+  return subjectPrincipal->GetUserContextId() == userContextId;
+}
+
+nsresult nsWindowWatcher::CreateChromeWindow(nsIWebBrowserChrome* aParentChrome,
+                                             uint32_t aChromeFlags,
+                                             nsIOpenWindowInfo* aOpenWindowInfo,
+                                             nsIWebBrowserChrome** aResult) {
+  if (NS_WARN_IF(!mWindowCreator)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  bool cancel = false;
+  if (aChromeFlags & nsIWebBrowserChrome::CHROME_OPENAS_DIALOG) {
+    // If there are any drag and drop operations in flight, try to end them.
+    nsCOMPtr<nsIDragService> ds =
+        do_GetService("@mozilla.org/widget/dragservice;1");
+    if (ds) {
+      ds->EndDragSession(true, 0);
+    }
+  }
+  nsCOMPtr<nsIWebBrowserChrome> newWindowChrome;
+  nsresult rv = mWindowCreator->CreateChromeWindow(
+      aParentChrome, aChromeFlags, aOpenWindowInfo, &cancel,
+      getter_AddRefs(newWindowChrome));
+
+  if (NS_SUCCEEDED(rv) && cancel) {
+    newWindowChrome = nullptr;
+    return NS_ERROR_ABORT;
+  }
+
+  newWindowChrome.forget(aResult);
+  return NS_OK;
+}
+
+/**
+ * Disable persistence of size/position in popups (determined by
+ * determining whether the features parameter specifies width or height
+ * in any way). We consider any overriding of the window's size or position
+ * in the open call as disabling persistence of those attributes.
+ * Popup windows (which should not persist size or position) generally set
+ * the size.
+ *
+ * @param aFeatures
+ *        The features that was used to open the window.
+ * @param aTreeOwner
+ *        The nsIDocShellTreeOwner of the newly opened window. If null,
+ *        this function is a no-op.
+ */
+static void MaybeDisablePersistence(const SizeSpec& aSizeSpec,
+                                    nsIDocShellTreeOwner* aTreeOwner) {
+  if (!aTreeOwner) {
+    return;
+  }
+
+  if (aSizeSpec.SizeSpecified()) {
+    aTreeOwner->SetPersistence(false, false, false);
+  }
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::OpenWindowWithRemoteTab(
+    nsIRemoteTab* aRemoteTab, const WindowFeatures& aFeatures,
+    const UserActivation::Modifiers& aModifiers, bool aCalledFromJS,
+    float aOpenerFullZoom, nsIOpenWindowInfo* aOpenWindowInfo,
+    nsIRemoteTab** aResult) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(mWindowCreator);
+
+  if (!nsContentUtils::IsSafeToRunScript()) {
+    nsContentUtils::WarnScriptWasIgnored(nullptr);
+    return NS_ERROR_FAILURE;
+  }
+
+  if (NS_WARN_IF(!mWindowCreator)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  bool isFissionWindow = FissionAutostart();
+  bool isPrivateBrowsingWindow =
+      StaticPrefs::browser_privatebrowsing_autostart();
+
+  nsCOMPtr<nsPIDOMWindowOuter> parentWindowOuter;
+  RefPtr<BrowsingContext> parentBC = aOpenWindowInfo->GetParent();
+  if (parentBC) {
+    RefPtr<Element> browserElement = parentBC->Top()->GetEmbedderElement();
+    if (browserElement && browserElement->GetOwnerGlobal() &&
+        browserElement->GetOwnerGlobal()->GetAsInnerWindow()) {
+      parentWindowOuter = browserElement->GetOwnerGlobal()
+                              ->GetAsInnerWindow()
+                              ->GetOuterWindow();
+    }
+
+    isFissionWindow = parentBC->UseRemoteSubframes();
+    isPrivateBrowsingWindow =
+        isPrivateBrowsingWindow || parentBC->UsePrivateBrowsing();
+  }
+
+  if (!parentWindowOuter) {
+    // We couldn't find a browser window for the opener, so either we
+    // never were passed aRemoteTab, the window is closed,
+    // or it's in the process of closing. Either way, we'll use
+    // the most recently opened browser window instead.
+    parentWindowOuter = nsContentUtils::GetMostRecentNonPBWindow();
+  }
+
+  if (NS_WARN_IF(!parentWindowOuter)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsCOMPtr<nsIDocShellTreeOwner> parentTreeOwner =
+      parentWindowOuter->GetTreeOwner();
+  if (NS_WARN_IF(!parentTreeOwner)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (NS_WARN_IF(!mWindowCreator)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // get various interfaces for aDocShellItem, used throughout this method
+  CSSToDesktopScale cssToDesktopScale(1.0f);
+  if (nsCOMPtr<nsIBaseWindow> win = do_QueryInterface(parentTreeOwner)) {
+    cssToDesktopScale = win->GetUnscaledCSSToDesktopScale();
+  }
+  SizeSpec sizeSpec = CalcSizeSpec(aFeatures, false, cssToDesktopScale);
+  sizeSpec.ScaleBy(aOpenerFullZoom);
+
+  // This is not initiated by window.open call in content context, and we
+  // don't need to propagate isPopupRequested out-parameter to the resulting
+  // browsing context.
+  bool unused = false;
+  uint32_t chromeFlags =
+      CalculateChromeFlagsForContent(aFeatures, aModifiers, &unused);
+
+  if (isPrivateBrowsingWindow) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW;
+  }
+
+  // A content process has asked for a new window, which implies
+  // that the new window will need to be remote.
+  chromeFlags |= nsIWebBrowserChrome::CHROME_REMOTE_WINDOW;
+
+  if (isFissionWindow) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_FISSION_WINDOW;
+  }
+
+  nsCOMPtr<nsIWebBrowserChrome> parentChrome(do_GetInterface(parentTreeOwner));
+  nsCOMPtr<nsIWebBrowserChrome> newWindowChrome;
+
+  CreateChromeWindow(parentChrome, chromeFlags, aOpenWindowInfo,
+                     getter_AddRefs(newWindowChrome));
+
+  if (NS_WARN_IF(!newWindowChrome)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsCOMPtr<nsIDocShellTreeItem> chromeTreeItem =
+      do_GetInterface(newWindowChrome);
+  if (NS_WARN_IF(!chromeTreeItem)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsCOMPtr<nsIDocShellTreeOwner> chromeTreeOwner;
+  chromeTreeItem->GetTreeOwner(getter_AddRefs(chromeTreeOwner));
+  if (NS_WARN_IF(!chromeTreeOwner)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsCOMPtr<nsILoadContext> chromeContext = do_QueryInterface(chromeTreeItem);
+  if (NS_WARN_IF(!chromeContext)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  MOZ_ASSERT(chromeContext->UsePrivateBrowsing() == isPrivateBrowsingWindow);
+  MOZ_ASSERT(chromeContext->UseRemoteSubframes() == isFissionWindow);
+
+  // Tabs opened from a content process can only open new windows
+  // that will also run with out-of-process tabs.
+  MOZ_ASSERT(chromeContext->UseRemoteTabs());
+
+  MaybeDisablePersistence(sizeSpec, chromeTreeOwner);
+
+  SizeOpenedWindow(chromeTreeOwner, parentWindowOuter, false, sizeSpec);
+
+  nsCOMPtr<nsIRemoteTab> newBrowserParent;
+  chromeTreeOwner->GetPrimaryRemoteTab(getter_AddRefs(newBrowserParent));
+  if (NS_WARN_IF(!newBrowserParent)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  newBrowserParent.forget(aResult);
+  return NS_OK;
+}
+
+nsresult nsWindowWatcher::OpenWindowInternal(
+    mozIDOMWindowProxy* aParent, const nsACString& aUrl,
+    const nsACString& aName, const nsACString& aFeatures,
+    const mozilla::dom::UserActivation::Modifiers& aModifiers,
+    bool aCalledFromJS, bool aDialog, bool aNavigate, nsIArray* aArgv,
+    bool aIsPopupSpam, bool aForceNoOpener, bool aForceNoReferrer,
+    PrintKind aPrintKind, nsDocShellLoadState* aLoadState,
+    BrowsingContext** aResult) {
+  MOZ_ASSERT_IF(aForceNoReferrer, aForceNoOpener);
+
+  nsresult rv = NS_OK;
+  bool isNewToplevelWindow = false;
+  bool windowIsNew = false;
+  bool windowNeedsName = false;
+  bool windowIsModal = false;
+  bool uriToLoadIsChrome = false;
+
+  uint32_t chromeFlags;
+  nsAutoString name;           // string version of aName
+  nsCOMPtr<nsIURI> uriToLoad;  // from aUrl, if any
+  nsCOMPtr<nsIDocShellTreeOwner>
+      parentTreeOwner;               // from the parent window, if any
+  RefPtr<BrowsingContext> targetBC;  // from the new window
+
+  nsCOMPtr<nsPIDOMWindowOuter> parentOuterWin =
+      aParent ? nsPIDOMWindowOuter::From(aParent) : nullptr;
+
+  NS_ENSURE_ARG_POINTER(aResult);
+  *aResult = nullptr;
+
+  if (!nsContentUtils::IsSafeToRunScript()) {
+    nsContentUtils::WarnScriptWasIgnored(nullptr);
+    return NS_ERROR_FAILURE;
+  }
+
+  if (parentOuterWin) {
+    parentTreeOwner = parentOuterWin->GetTreeOwner();
+  }
+
+  // We expect BrowserParent to have provided us the absolute URI of the window
+  // we're to open, so there's no need to call URIfromURL (or more importantly,
+  // to check for a chrome URI, which cannot be opened from a remote tab).
+  if (!aUrl.IsVoid()) {
+    rv = URIfromURL(aUrl, aParent, getter_AddRefs(uriToLoad));
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+    uriToLoadIsChrome = uriToLoad->SchemeIs("chrome");
+  }
+
+  bool nameSpecified = false;
+  if (!aName.IsEmpty()) {
+    CopyUTF8toUTF16(aName, name);
+    nameSpecified = true;
+  } else {
+    name.SetIsVoid(true);
+  }
+
+  WindowFeatures features;
+  nsAutoCString featuresStr;
+  if (!aFeatures.IsEmpty()) {
+    featuresStr.Assign(aFeatures);
+    features.Tokenize(featuresStr);
+  } else {
+    featuresStr.SetIsVoid(true);
+  }
+
+  RefPtr<BrowsingContext> parentBC(
+      parentOuterWin ? parentOuterWin->GetBrowsingContext() : nullptr);
+  nsCOMPtr<nsIDocShell> parentDocShell(parentBC ? parentBC->GetDocShell()
+                                                : nullptr);
+  RefPtr<Document> parentDoc(parentOuterWin ? parentOuterWin->GetDoc()
+                                            : nullptr);
+  nsCOMPtr<nsPIDOMWindowInner> parentInnerWin(
+      parentOuterWin ? parentOuterWin->GetCurrentInnerWindow() : nullptr);
+
+  // Return null for any attempt to trigger a load from a discarded browsing
+  // context. The spec is non-normative, and doesn't specify what should happen
+  // when window.open is called on a window with a null browsing context, but it
+  // does give us broad discretion over when we can decide to ignore an open
+  // request and return null.
+  //
+  // Regardless, we cannot trigger a cross-process load from a discarded
+  // browsing context, and ideally we should behave consistently whether a load
+  // is same-process or cross-process.
+  if (parentBC && parentBC->IsDiscarded()) {
+    return NS_ERROR_ABORT;
+  }
+
+  // If no parent, consider it chrome when running in the parent process.
+  bool hasChromeParent = !XRE_IsContentProcess();
+  if (aParent) {
+    // Check if the parent document has chrome privileges.
+    hasChromeParent = parentDoc && nsContentUtils::IsChromeDoc(parentDoc);
+  }
+
+  bool isCallerChrome = nsContentUtils::LegacyIsCallerChromeOrNativeCode();
+
+  // try to find an extant browsing context with the given name
+  if (!name.IsEmpty() &&
+      (!aForceNoOpener || nsContentUtils::IsSpecialName(name))) {
+    if (parentInnerWin && parentInnerWin->GetWindowGlobalChild()) {
+      // If we have a parent window, perform the look-up relative to the parent
+      // inner window.
+      targetBC =
+          parentInnerWin->GetWindowGlobalChild()->FindBrowsingContextWithName(
+              name);
+    } else if (hasChromeParent && isCallerChrome &&
+               !nsContentUtils::IsSpecialName(name)) {
+      // Otherwise, if this call is from chrome, perform the lookup relative
+      // to the system group.
+      nsCOMPtr<mozIDOMWindowProxy> chromeWindow;
+      MOZ_ALWAYS_SUCCEEDS(GetWindowByName(name, getter_AddRefs(chromeWindow)));
+      if (chromeWindow) {
+        targetBC = nsPIDOMWindowOuter::From(chromeWindow)->GetBrowsingContext();
+      }
+    }
+  }
+
+  // Do sandbox checks here, instead of waiting until nsIDocShell::LoadURI.
+  // The state of the window can change before this call and if we are blocked
+  // because of sandboxing, we wouldn't want that to happen.
+  if (parentBC && parentBC->IsSandboxedFrom(targetBC)) {
+    return NS_ERROR_DOM_INVALID_ACCESS_ERR;
+  }
+
+  // If our target BrowsingContext is still pending initialization, ignore the
+  // navigation request targeting it.
+  if (targetBC && NS_WARN_IF(targetBC->GetPendingInitialization())) {
+    return NS_ERROR_ABORT;
+  }
+
+  // no extant window? make a new one.
+
+  CSSToDesktopScale cssToDesktopScale(1.0);
+  if (nsCOMPtr<nsIBaseWindow> win = do_QueryInterface(parentDocShell)) {
+    cssToDesktopScale = win->GetUnscaledCSSToDesktopScale();
+  }
+  SizeSpec sizeSpec =
+      CalcSizeSpec(features, hasChromeParent, cssToDesktopScale);
+  sizeSpec.ScaleBy(parentBC ? parentBC->FullZoom() : 1.0f);
+
+  bool isPopupRequested = false;
+
+  // Make sure we calculate the chromeFlags *before* we push the
+  // callee context onto the context stack so that
+  // the calculation sees the actual caller when doing its
+  // security checks.
+  if (hasChromeParent && isCallerChrome && XRE_IsParentProcess()) {
+    chromeFlags =
+        CalculateChromeFlagsForSystem(features, aDialog, uriToLoadIsChrome);
+  } else {
+    MOZ_DIAGNOSTIC_ASSERT(parentBC && parentBC->IsContent(),
+                          "content caller must provide content parent");
+    chromeFlags =
+        CalculateChromeFlagsForContent(features, aModifiers, &isPopupRequested);
+
+    if (aDialog) {
+      MOZ_ASSERT(XRE_IsParentProcess());
+      chromeFlags |= nsIWebBrowserChrome::CHROME_OPENAS_DIALOG;
+    }
+  }
+
+  bool windowTypeIsChrome =
+      chromeFlags & nsIWebBrowserChrome::CHROME_OPENAS_CHROME;
+
+  if (parentBC && !aForceNoOpener) {
+    if (parentBC->IsChrome() && !windowTypeIsChrome) {
+      NS_WARNING(
+          "Content windows may never have chrome windows as their openers.");
+      return NS_ERROR_INVALID_ARG;
+    }
+    if (parentBC->IsContent() && windowTypeIsChrome) {
+      NS_WARNING(
+          "Chrome windows may never have content windows as their openers.");
+      return NS_ERROR_INVALID_ARG;
+    }
+  }
+
+  // If we're opening a content window from a content window, we need to exactly
+  // inherit fission and e10s status flags from parentBC. Only new toplevel
+  // windows may change these options.
+  if (parentBC && parentBC->IsContent() && !windowTypeIsChrome) {
+    chromeFlags &= ~(nsIWebBrowserChrome::CHROME_REMOTE_WINDOW |
+                     nsIWebBrowserChrome::CHROME_FISSION_WINDOW);
+    if (parentBC->UseRemoteTabs()) {
+      chromeFlags |= nsIWebBrowserChrome::CHROME_REMOTE_WINDOW;
+    }
+    if (parentBC->UseRemoteSubframes()) {
+      chromeFlags |= nsIWebBrowserChrome::CHROME_FISSION_WINDOW;
+    }
+  }
+
+  // XXXbz Why is an AutoJSAPI good enough here?  Wouldn't AutoEntryScript (so
+  // we affect the entry global) make more sense?  Or do we just want to affect
+  // GetSubjectPrincipal()?
+  dom::AutoJSAPI jsapiChromeGuard;
+
+  if (isCallerChrome && !hasChromeParent && !windowTypeIsChrome) {
+    // open() is called from chrome on a non-chrome window, initialize an
+    // AutoJSAPI with the callee to prevent the caller's privileges from leaking
+    // into code that runs while opening the new window.
+    //
+    // The reasoning for this is in bug 289204. Basically, chrome sometimes does
+    // someContentWindow.open(untrustedURL), and wants to be insulated from
+    // nasty javascript: URLs and such. But there are also cases where we create
+    // a window parented to a content window (such as a download dialog),
+    // usually directly with nsIWindowWatcher. In those cases, we want the
+    // principal of the initial about:blank document to be system, so that the
+    // subsequent XUL load can reuse the inner window and avoid blowing away
+    // expandos. As such, we decide whether to load with the principal of the
+    // caller or of the parent based on whether the docshell type is chrome or
+    // content.
+
+    nsCOMPtr<nsIGlobalObject> parentGlobalObject = do_QueryInterface(aParent);
+    if (!aParent) {
+      jsapiChromeGuard.Init();
+    } else if (NS_WARN_IF(!jsapiChromeGuard.Init(parentGlobalObject))) {
+      return NS_ERROR_UNEXPECTED;
+    }
+  }
+
+  // Now that the jsapiChromeGuard has been set, fetch the system principal
+  // potentially configured by it. We want to make sure to respect any principal
+  // changes imposed by that guard throughout this function.
+  //
+  // Note: The check for the current JSContext isn't necessarily sensical.
+  // It's just designed to preserve old semantics during a mass-conversion
+  // patch.
+  // Bug 1498605 verify usages of systemPrincipal here
+  JSContext* cx = nsContentUtils::GetCurrentJSContext();
+  nsCOMPtr<nsIPrincipal> subjectPrincipal =
+      cx ? nsContentUtils::SubjectPrincipal()
+         : nsContentUtils::GetSystemPrincipal();
+  MOZ_ASSERT(subjectPrincipal);
+
+  nsCOMPtr<nsIPrincipal> newWindowPrincipal;
+  if (!targetBC) {
+    if (windowTypeIsChrome) {
+      // If we are creating a chrome window, we must be called with a system
+      // principal, and should inherit that for the new chrome window.
+      MOZ_RELEASE_ASSERT(subjectPrincipal->IsSystemPrincipal(),
+                         "Only system principals can create chrome windows");
+      newWindowPrincipal = subjectPrincipal;
+    } else if (nsContentUtils::IsSystemOrExpandedPrincipal(subjectPrincipal)) {
+      // Don't allow initial about:blank documents to inherit a system or
+      // expanded principal, instead replace it with a null principal. We can't
+      // inherit origin attributes from the system principal, so use the parent
+      // BC if it's available.
+      if (parentBC) {
+        newWindowPrincipal =
+            NullPrincipal::Create(parentBC->OriginAttributesRef());
+      } else {
+        newWindowPrincipal = NullPrincipal::CreateWithoutOriginAttributes();
+      }
+    } else if (aForceNoOpener) {
+      // If we're opening a new window with noopener, create a new opaque
+      // principal for the new window, rather than re-using the existing
+      // principal.
+      newWindowPrincipal =
+          NullPrincipal::CreateWithInheritedAttributes(subjectPrincipal);
+    } else {
+      // Finally, if there's an opener relationship and it's not a special
+      // principal, we should inherit that principal for the new window.
+      newWindowPrincipal = subjectPrincipal;
+    }
+  }
+
+  // Information used when opening new content windows. This object will be
+  // passed through to the inner nsFrameLoader.
+  RefPtr<nsOpenWindowInfo> openWindowInfo;
+  if (!targetBC && !windowTypeIsChrome) {
+    openWindowInfo = new nsOpenWindowInfo();
+    openWindowInfo->mForceNoOpener = aForceNoOpener;
+    openWindowInfo->mParent = parentBC;
+    openWindowInfo->mIsForPrinting = aPrintKind != PRINT_NONE;
+    openWindowInfo->mIsForWindowDotPrint = aPrintKind == PRINT_WINDOW_DOT_PRINT;
+
+    // We're going to want the window to be immediately available, meaning we
+    // want it to match the current remoteness.
+    openWindowInfo->mIsRemote = XRE_IsContentProcess();
+
+    // Inherit our OriginAttributes from the computed new window principal.
+    MOZ_ASSERT(
+        newWindowPrincipal &&
+        !nsContentUtils::IsSystemOrExpandedPrincipal(newWindowPrincipal));
+    openWindowInfo->mOriginAttributes =
+        newWindowPrincipal->OriginAttributesRef();
+
+    MOZ_DIAGNOSTIC_ASSERT(
+        !parentBC || openWindowInfo->mOriginAttributes.EqualsIgnoringFPD(
+                         parentBC->OriginAttributesRef()),
+        "subject principal origin attributes doesn't match opener");
+  }
+
+  uint32_t activeDocsSandboxFlags = 0;
+  nsCOMPtr<nsIContentSecurityPolicy> cspToInheritForAboutBlank;
+  Maybe<nsILoadInfo::CrossOriginEmbedderPolicy> coepToInheritForAboutBlank;
+  if (!targetBC) {
+    // We're going to either open up a new window ourselves or ask a
+    // nsIWindowProvider for one.  In either case, we'll want to set the right
+    // name on it.
+    windowNeedsName = true;
+
+    // If the parent trying to open a new window is sandboxed
+    // without 'allow-popups', this is not allowed and we fail here.
+    if (parentDoc) {
+      // Save sandbox flags for copying to new browsing context (docShell).
+      activeDocsSandboxFlags = parentDoc->GetSandboxFlags();
+
+      if (!aForceNoOpener) {
+        cspToInheritForAboutBlank = parentDoc->GetCsp();
+        coepToInheritForAboutBlank = parentDoc->GetEmbedderPolicy();
+      }
+
+      // Check to see if this frame is allowed to navigate, but don't check if
+      // we're printing, as that's not a real navigation.
+      if (aPrintKind == PRINT_NONE &&
+          (activeDocsSandboxFlags & SANDBOXED_AUXILIARY_NAVIGATION)) {
+        return NS_ERROR_DOM_INVALID_ACCESS_ERR;
+      }
+    }
+
+    // Now check whether it's ok to ask a window provider for a window.  Don't
+    // do it if we're opening a dialog or if our parent is a chrome window or
+    // if we're opening something that has modal, dialog, or chrome flags set.
+    if (parentTreeOwner && !aDialog && parentBC->IsContent() &&
+        !(chromeFlags & (nsIWebBrowserChrome::CHROME_MODAL |
+                         nsIWebBrowserChrome::CHROME_OPENAS_DIALOG |
+                         nsIWebBrowserChrome::CHROME_OPENAS_CHROME))) {
+      MOZ_ASSERT(openWindowInfo);
+
+      nsCOMPtr<nsIWindowProvider> provider = do_GetInterface(parentTreeOwner);
+      if (provider) {
+        rv = provider->ProvideWindow(openWindowInfo, chromeFlags, aCalledFromJS,
+                                     uriToLoad, name, featuresStr, aModifiers,
+                                     aForceNoOpener, aForceNoReferrer,
+                                     isPopupRequested, aLoadState, &windowIsNew,
+                                     getter_AddRefs(targetBC));
+
+        if (NS_SUCCEEDED(rv) && targetBC) {
+          nsCOMPtr<nsIDocShell> newDocShell = targetBC->GetDocShell();
+
+          // If this is a new window, but it's incompatible with the current
+          // userContextId, we ignore it and we pretend that nothing has been
+          // returned by ProvideWindow.
+          if (!windowIsNew && newDocShell) {
+            if (!CheckUserContextCompatibility(newDocShell)) {
+              targetBC = nullptr;
+              windowIsNew = false;
+            }
+          }
+
+        } else if (rv == NS_ERROR_ABORT) {
+          // NS_ERROR_ABORT means the window provider has flat-out rejected
+          // the open-window call and we should bail.  Don't return an error
+          // here, because our caller may propagate that error, which might
+          // cause e.g. window.open to throw!  Just return null for our out
+          // param.
+          return NS_OK;
+        }
+      }
+    }
+  }
+
+  bool newWindowShouldBeModal = false;
+  bool parentIsModal = false;
+  if (!targetBC) {
+    if (XRE_IsContentProcess()) {
+      // If our window provider failed to provide a window in the content
+      // process, we cannot recover. Reject the window open request and bail.
+      return NS_OK;
+    }
+
+    windowIsNew = true;
+    isNewToplevelWindow = true;
+
+    nsCOMPtr<nsIWebBrowserChrome> parentChrome(
+        do_GetInterface(parentTreeOwner));
+
+    // is the parent (if any) modal? if so, we must be, too.
+    bool weAreModal = (chromeFlags & nsIWebBrowserChrome::CHROME_MODAL) != 0;
+    newWindowShouldBeModal = weAreModal;
+    if (!weAreModal && parentChrome) {
+      parentChrome->IsWindowModal(&weAreModal);
+      parentIsModal = weAreModal;
+    }
+
+    if (weAreModal) {
+      windowIsModal = true;
+      // in case we added this because weAreModal
+      chromeFlags |= nsIWebBrowserChrome::CHROME_MODAL |
+                     nsIWebBrowserChrome::CHROME_DEPENDENT;
+    }
+
+    // Make sure to not create modal windows if our parent is invisible and
+    // isn't a chrome window.  Otherwise we can end up in a bizarre situation
+    // where we can't shut down because an invisible window is open.  If
+    // someone tries to do this, throw.
+    if (!hasChromeParent && (chromeFlags & nsIWebBrowserChrome::CHROME_MODAL)) {
+      nsCOMPtr<nsIBaseWindow> parentWindow(do_GetInterface(parentTreeOwner));
+      nsCOMPtr<nsIWidget> parentWidget;
+      if (parentWindow) {
+        parentWindow->GetMainWidget(getter_AddRefs(parentWidget));
+      }
+      // NOTE: the logic for this visibility check is duplicated in
+      // nsIDOMWindowUtils::isParentWindowMainWidgetVisible - if we change
+      // how a window is determined "visible" in this context then we should
+      // also adjust that attribute and/or any consumers of it...
+      if (parentWidget && !parentWidget->IsVisible()) {
+        return NS_ERROR_NOT_AVAILABLE;
+      }
+    }
+
+    NS_ASSERTION(mWindowCreator,
+                 "attempted to open a new window with no WindowCreator");
+    rv = NS_ERROR_FAILURE;
+    if (mWindowCreator) {
+      nsCOMPtr<nsIWebBrowserChrome> newChrome;
+
+      nsCOMPtr<nsPIDOMWindowInner> parentTopInnerWindow;
+      if (parentOuterWin) {
+        nsCOMPtr<nsPIDOMWindowOuter> parentTopWindow =
+            parentOuterWin->GetInProcessTop();
+        if (parentTopWindow) {
+          parentTopInnerWindow = parentTopWindow->GetCurrentInnerWindow();
+        }
+      }
+
+      if (parentTopInnerWindow) {
+        parentTopInnerWindow->Suspend();
+      }
+
+      /* We can give the window creator some hints. The only hint at this time
+         is whether the opening window is in a situation that's likely to mean
+         this is an unrequested popup window we're creating. However we're not
+         completely honest: we clear that indicator if the opener is chrome, so
+         that the downstream consumer can treat the indicator to mean simply
+         that the new window is subject to popup control. */
+      rv = CreateChromeWindow(parentChrome, chromeFlags, openWindowInfo,
+                              getter_AddRefs(newChrome));
+      if (parentTopInnerWindow) {
+        parentTopInnerWindow->Resume();
+      }
+
+      if (newChrome) {
+        /* It might be a chrome AppWindow, in which case it won't have
+            an nsIDOMWindow (primary content shell). But in that case, it'll
+            be able to hand over an nsIDocShellTreeItem directly. */
+        nsCOMPtr<nsPIDOMWindowOuter> newWindow(do_GetInterface(newChrome));
+        nsCOMPtr<nsIDocShellTreeItem> newDocShellItem;
+        if (newWindow) {
+          newDocShellItem = newWindow->GetDocShell();
+        }
+        if (!newDocShellItem) {
+          newDocShellItem = do_GetInterface(newChrome);
+        }
+        if (!newDocShellItem) {
+          rv = NS_ERROR_FAILURE;
+        }
+        targetBC = newDocShellItem->GetBrowsingContext();
+      }
+    }
+  }
+
+  // better have a window to use by this point
+  if (!targetBC) {
+    return rv;
+  }
+
+  // If our parent is sandboxed, set it as the one permitted sandboxed navigator
+  // on the new window we're opening.
+  if (activeDocsSandboxFlags && parentBC) {
+    MOZ_ALWAYS_SUCCEEDS(targetBC->SetOnePermittedSandboxedNavigator(parentBC));
+  }
+
+  if (!aForceNoOpener && parentBC) {
+    // If we've created a new content window, its opener should have been set
+    // when its BrowsingContext was created, in order to ensure that the context
+    // is loaded within the correct BrowsingContextGroup.
+    if (windowIsNew && targetBC->IsContent()) {
+      if (parentBC->IsDiscarded()) {
+        // If the parent BC was discarded in a nested event loop before we got
+        // to this point, we can't set it as the opener. Ideally we would still
+        // set `HadOriginalOpener()` in that case, but that's somewhat
+        // nontrivial, and not worth the effort given the nature of the corner
+        // case (see comment in `nsFrameLoader::CreateBrowsingContext`.
+        MOZ_RELEASE_ASSERT(targetBC->GetOpenerId() == parentBC->Id() ||
+                           targetBC->GetOpenerId() == 0);
+      } else {
+        MOZ_RELEASE_ASSERT(targetBC->GetOpenerId() == parentBC->Id());
+        MOZ_RELEASE_ASSERT(targetBC->HadOriginalOpener());
+      }
+    } else {
+      // Update the opener for an existing or chrome BC.
+      targetBC->SetOpener(parentBC);
+    }
+  }
+
+  RefPtr<nsDocShell> targetDocShell(nsDocShell::Cast(targetBC->GetDocShell()));
+
+  // As required by spec, new windows always start out same-process, even if the
+  // URL being loaded will eventually load in a new process.
+  MOZ_DIAGNOSTIC_ASSERT(!windowIsNew || targetDocShell);
+  // New top-level windows are only opened in the parent process and are, by
+  // definition, always in-process.
+  MOZ_DIAGNOSTIC_ASSERT(!isNewToplevelWindow || targetDocShell);
+
+  // Copy sandbox flags to the new window if activeDocsSandboxFlags says to do
+  // so.  Note that it's only nonzero if the window is new, so clobbering
+  // sandbox flags on the window makes sense in that case.
+  if (activeDocsSandboxFlags &
+      SANDBOX_PROPAGATES_TO_AUXILIARY_BROWSING_CONTEXTS) {
+    MOZ_ASSERT(windowIsNew, "Should only get here for new windows");
+    MOZ_ALWAYS_SUCCEEDS(targetBC->SetSandboxFlags(activeDocsSandboxFlags));
+    MOZ_ALWAYS_SUCCEEDS(
+        targetBC->SetInitialSandboxFlags(targetBC->GetSandboxFlags()));
+  }
+
+  RefPtr<nsGlobalWindowOuter> targetOuterWin(
+      nsGlobalWindowOuter::Cast(targetBC->GetDOMWindow()));
+#ifdef DEBUG
+  if (targetOuterWin && windowIsNew) {
+    // Assert that we're not loading things right now.  If we are, when
+    // that load completes it will clobber whatever principals we set up
+    // on this new window!
+    nsCOMPtr<nsIChannel> chan;
+    targetDocShell->GetDocumentChannel(getter_AddRefs(chan));
+    MOZ_ASSERT(!chan, "Why is there a document channel?");
+
+    if (RefPtr<Document> doc = targetOuterWin->GetExtantDoc()) {
+      MOZ_ASSERT(doc->IsInitialDocument(),
+                 "New window's document should be an initial document");
+    }
+  }
+#endif
+
+  MOZ_ASSERT(targetOuterWin || !windowIsNew,
+             "New windows are always created in-process");
+
+  *aResult = do_AddRef(targetBC).take();
+
+  if (isNewToplevelWindow) {
+    nsCOMPtr<nsIDocShellTreeOwner> newTreeOwner;
+    targetDocShell->GetTreeOwner(getter_AddRefs(newTreeOwner));
+    MaybeDisablePersistence(sizeSpec, newTreeOwner);
+  }
+
+  if (aDialog && aArgv) {
+    MOZ_ASSERT(targetOuterWin);
+    NS_ENSURE_TRUE(targetOuterWin, NS_ERROR_UNEXPECTED);
+
+    // Set the args on the new window.
+    MOZ_TRY(targetOuterWin->SetArguments(aArgv));
+  }
+
+  /* allow a window that we found by name to keep its name (important for cases
+     like _self where the given name is different (and invalid)).  Also, _blank
+     is not a window name. */
+  if (windowNeedsName) {
+    if (nameSpecified && !name.LowerCaseEqualsLiteral("_blank")) {
+      MOZ_ALWAYS_SUCCEEDS(targetBC->SetName(name));
+    } else {
+      MOZ_ALWAYS_SUCCEEDS(targetBC->SetName(u""_ns));
+    }
+  }
+
+  // Now we have to set the right opener principal on the new window.  Note
+  // that we have to do this _before_ starting any URI loads, thanks to the
+  // sync nature of javascript: loads.
+
+  if (windowIsNew) {
+    MOZ_DIAGNOSTIC_ASSERT(
+        !targetBC->IsContent() ||
+        newWindowPrincipal->OriginAttributesRef().EqualsIgnoringFPD(
+            targetBC->OriginAttributesRef()));
+
+    bool autoPrivateBrowsing = StaticPrefs::browser_privatebrowsing_autostart();
+
+    if (!autoPrivateBrowsing &&
+        (chromeFlags & nsIWebBrowserChrome::CHROME_NON_PRIVATE_WINDOW)) {
+      if (targetBC->IsChrome()) {
+        targetBC->SetUsePrivateBrowsing(false);
+      }
+      MOZ_DIAGNOSTIC_ASSERT(
+          !targetBC->UsePrivateBrowsing(),
+          "CHROME_NON_PRIVATE_WINDOW passed, but got private window");
+    } else if (autoPrivateBrowsing ||
+               (chromeFlags & nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW)) {
+      if (targetBC->IsChrome()) {
+        targetBC->SetUsePrivateBrowsing(true);
+      }
+      MOZ_DIAGNOSTIC_ASSERT(
+          targetBC->UsePrivateBrowsing(),
+          "CHROME_PRIVATE_WINDOW passed, but got non-private window");
+    }
+
+    // Now set the opener principal on the new window.  Note that we need to do
+    // this no matter whether we were opened from JS; if there is nothing on
+    // the JS stack, just use the principal of our parent window.  In those
+    // cases we do _not_ set the parent window principal as the owner of the
+    // load--since we really don't know who the owner is, just leave it null.
+    NS_ASSERTION(targetOuterWin == targetDocShell->GetWindow(),
+                 "Different windows??");
+
+    // Initialize the principal of the initial about:blank document. For
+    // toplevel windows, this call may have already happened when the window was
+    // created, but SetInitialPrincipal is safe to call multiple times.
+    if (targetOuterWin) {
+      MOZ_ASSERT(windowIsNew);
+      MOZ_ASSERT(!targetOuterWin->GetSameProcessOpener() ||
+                 targetOuterWin->GetSameProcessOpener() == aParent);
+      targetOuterWin->SetInitialPrincipal(newWindowPrincipal,
+                                          cspToInheritForAboutBlank,
+                                          coepToInheritForAboutBlank);
+
+      if (aIsPopupSpam) {
+        MOZ_ASSERT(!targetBC->GetIsPopupSpam(),
+                   "Who marked it as popup spam already???");
+        // Make sure we don't mess up our counter even if the above assert
+        // fails.
+        if (!targetBC->GetIsPopupSpam()) {
+          MOZ_ALWAYS_SUCCEEDS(targetBC->SetIsPopupSpam(true));
+        }
+      }
+    }
+
+    // Copy the current session storage for the current domain. Don't perform
+    // the copy if we're forcing noopener, however.
+    if (!aForceNoOpener && subjectPrincipal && parentDocShell &&
+        targetDocShell) {
+      const RefPtr<SessionStorageManager> parentStorageManager =
+          parentDocShell->GetBrowsingContext()->GetSessionStorageManager();
+      const RefPtr<SessionStorageManager> newStorageManager =
+          targetDocShell->GetBrowsingContext()->GetSessionStorageManager();
+
+      if (parentStorageManager && newStorageManager) {
+        RefPtr<Storage> storage;
+        parentStorageManager->GetStorage(
+            parentInnerWin, subjectPrincipal, subjectPrincipal,
+            targetBC->UsePrivateBrowsing(), getter_AddRefs(storage));
+        if (storage) {
+          newStorageManager->CloneStorage(storage);
+        }
+      }
+    }
+  }
+
+  // We rely on CalculateChromeFlags to decide whether remote (out-of-process)
+  // tabs should be used.
+  MOZ_DIAGNOSTIC_ASSERT(
+      targetBC->UseRemoteTabs() ==
+      !!(chromeFlags & nsIWebBrowserChrome::CHROME_REMOTE_WINDOW));
+  MOZ_DIAGNOSTIC_ASSERT(
+      targetBC->UseRemoteSubframes() ==
+      !!(chromeFlags & nsIWebBrowserChrome::CHROME_FISSION_WINDOW));
+
+  RefPtr<nsDocShellLoadState> loadState = aLoadState;
+  if (uriToLoad && loadState) {
+    // If a URI was passed to this function, open that, not what was passed in
+    // the original LoadState. See Bug 1515433.
+    loadState->SetURI(uriToLoad);
+  } else if (uriToLoad && aNavigate && !loadState) {
+    RefPtr<WindowContext> context =
+        parentInnerWin ? parentInnerWin->GetWindowContext() : nullptr;
+    loadState = new nsDocShellLoadState(uriToLoad);
+
+    loadState->SetSourceBrowsingContext(parentBC);
+    loadState->SetAllowFocusMove(true);
+    loadState->SetHasValidUserGestureActivation(
+        context && context->HasValidTransientUserGestureActivation());
+    if (parentBC) {
+      loadState->SetTriggeringSandboxFlags(parentBC->GetSandboxFlags());
+    }
+
+    if (parentInnerWin) {
+      loadState->SetTriggeringWindowId(parentInnerWin->WindowID());
+      loadState->SetTriggeringStorageAccess(
+          parentInnerWin->UsingStorageAccess());
+    }
+
+    if (subjectPrincipal) {
+      loadState->SetTriggeringPrincipal(subjectPrincipal);
+    }
+#ifndef ANDROID
+    MOZ_ASSERT(subjectPrincipal,
+               "nsWindowWatcher: triggeringPrincipal required");
+#endif
+
+    if (!aForceNoReferrer) {
+      /* use the URL from the *extant* document, if any. The usual accessor
+         GetDocument will synchronously create an about:blank document if
+         it has no better answer, and we only care about a real document.
+         Also using GetDocument to force document creation seems to
+         screw up focus in the hidden window; see bug 36016.
+      */
+      RefPtr<Document> doc = GetEntryDocument();
+      if (!doc) {
+        doc = parentDoc;
+      }
+      if (doc) {
+        auto referrerInfo = MakeRefPtr<ReferrerInfo>(*doc);
+        loadState->SetReferrerInfo(referrerInfo);
+      }
+    }
+  }
+
+  if (loadState && cx) {
+    nsGlobalWindowInner* win = xpc::CurrentWindowOrNull(cx);
+    if (win) {
+      nsCOMPtr<nsIContentSecurityPolicy> csp = win->GetCsp();
+      loadState->SetCsp(csp);
+    }
+  }
+
+  if (isNewToplevelWindow) {
+    // Notify observers that the window is open and ready.
+    // The window has not yet started to load a document.
+    nsCOMPtr<nsIObserverService> obsSvc =
+        mozilla::services::GetObserverService();
+    if (obsSvc) {
+      obsSvc->NotifyObservers(ToSupports(targetOuterWin),
+                              "toplevel-window-ready", nullptr);
+    }
+  }
+
+  // Before loading the URI we want to be 100% sure that we use the correct
+  // userContextId.
+  MOZ_ASSERT_IF(targetDocShell, CheckUserContextCompatibility(targetDocShell));
+
+  // If this tab or window has been opened by a window.open call, we have to
+  // provide all the data needed to send a
+  // webNavigation.onCreatedNavigationTarget event.
+  if (parentDocShell && windowIsNew) {
+    nsCOMPtr<nsIObserverService> obsSvc =
+        mozilla::services::GetObserverService();
+
+    if (obsSvc) {
+      RefPtr<nsHashPropertyBag> props = new nsHashPropertyBag();
+
+      if (uriToLoad) {
+        // The url notified in the webNavigation.onCreatedNavigationTarget
+        // event.
+        props->SetPropertyAsACString(u"url"_ns, uriToLoad->GetSpecOrDefault());
+      }
+
+      props->SetPropertyAsInterface(u"sourceTabDocShell"_ns, parentDocShell);
+      props->SetPropertyAsInterface(u"createdTabDocShell"_ns,
+                                    ToSupports(targetDocShell));
+
+      obsSvc->NotifyObservers(static_cast<nsIPropertyBag2*>(props),
+                              "webNavigation-createdNavigationTarget-from-js",
+                              nullptr);
+    }
+  }
+
+  if (uriToLoad && aNavigate) {
+    uint32_t loadFlags = nsIWebNavigation::LOAD_FLAGS_NONE;
+    if (windowIsNew) {
+      loadFlags |= nsIWebNavigation::LOAD_FLAGS_FIRST_LOAD;
+
+      // Per spec, the explicit navigation to about:blank after the initial
+      // about:blank document in a new window does not occur, so there is no
+      // opportunity for it to inherit the source document's principal. This
+      // doesn't perfectly model this, as a noopener creation of `about:blank`
+      // will replace the global due to a principal mismatch, but it should be
+      // unobservable (bug 1694993).
+      // This isn't set for chrome windows, as an about:blank chrome document
+      // needs to inherit its principal from its opener.
+      if (aForceNoOpener && !windowTypeIsChrome) {
+        loadFlags |= nsIWebNavigation::LOAD_FLAGS_DISALLOW_INHERIT_PRINCIPAL;
+      }
+    }
+    loadState->SetLoadFlags(loadFlags);
+    loadState->SetFirstParty(true);
+
+    // Should this pay attention to errors returned by LoadURI?
+    targetBC->LoadURI(loadState);
+  }
+
+  if (isNewToplevelWindow) {
+    nsCOMPtr<nsIDocShellTreeOwner> newTreeOwner;
+    targetDocShell->GetTreeOwner(getter_AddRefs(newTreeOwner));
+    SizeOpenedWindow(newTreeOwner, aParent, isCallerChrome, sizeSpec);
+  }
+
+  if (windowIsModal) {
+    NS_ENSURE_TRUE(targetDocShell, NS_ERROR_NOT_IMPLEMENTED);
+
+    nsCOMPtr<nsIDocShellTreeOwner> newTreeOwner;
+    targetDocShell->GetTreeOwner(getter_AddRefs(newTreeOwner));
+    nsCOMPtr<nsIWebBrowserChrome> newChrome(do_GetInterface(newTreeOwner));
+
+    // Throw an exception here if no web browser chrome is available,
+    // we need that to show a modal window.
+    NS_ENSURE_TRUE(newChrome, NS_ERROR_NOT_AVAILABLE);
+
+    // Dispatch dialog events etc, but we only want to do that if
+    // we're opening a modal content window (the helper classes are
+    // no-ops if given no window), for chrome dialogs we don't want to
+    // do any of that (it's done elsewhere for us).
+    // Make sure we maintain the state on an outer window, because
+    // that's where it lives; inner windows assert if you try to
+    // maintain the state on them.
+    nsAutoWindowStateHelper windowStateHelper(parentOuterWin);
+
+    if (!windowStateHelper.DefaultEnabled()) {
+      // Default to cancel not opening the modal window.
+      NS_RELEASE(*aResult);
+
+      return NS_OK;
+    }
+
+    bool isAppModal = false;
+    nsCOMPtr<nsIBaseWindow> parentWindow(do_GetInterface(newTreeOwner));
+    nsCOMPtr<nsIWidget> parentWidget;
+    if (parentWindow) {
+      parentWindow->GetMainWidget(getter_AddRefs(parentWidget));
+      if (parentWidget) {
+        isAppModal = parentWidget->IsRunningAppModal();
+      }
+    }
+    if (parentWidget &&
+        ((!newWindowShouldBeModal && parentIsModal) || isAppModal)) {
+      parentWidget->SetFakeModal(true);
+    } else {
+      // Reset popup state while opening a modal dialog, and firing
+      // events about the dialog, to prevent the current state from
+      // being active the whole time a modal dialog is open.
+      AutoPopupStatePusher popupStatePusher(PopupBlocker::openAbused);
+
+      auto rv = newChrome->ShowAsModal();
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+  // If a website opens a popup exit DOM fullscreen
+  if (StaticPrefs::full_screen_api_exit_on_windowOpen() && aCalledFromJS &&
+      !hasChromeParent && !isCallerChrome && parentOuterWin) {
+    Document::AsyncExitFullscreen(parentOuterWin->GetDoc());
+  }
+
+  if (aForceNoOpener && windowIsNew) {
+    NS_RELEASE(*aResult);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::RegisterNotification(nsIObserver* aObserver) {
+  // just a convenience method; it delegates to nsIObserverService
+
+  if (!aObserver) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (!os) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = os->AddObserver(aObserver, "domwindowopened", false);
+  if (NS_SUCCEEDED(rv)) {
+    rv = os->AddObserver(aObserver, "domwindowclosed", false);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::UnregisterNotification(nsIObserver* aObserver) {
+  // just a convenience method; it delegates to nsIObserverService
+
+  if (!aObserver) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (!os) {
+    return NS_ERROR_FAILURE;
+  }
+
+  os->RemoveObserver(aObserver, "domwindowopened");
+  os->RemoveObserver(aObserver, "domwindowclosed");
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::GetWindowEnumerator(nsISimpleEnumerator** aResult) {
+  if (!aResult) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  MutexAutoLock lock(mListLock);
+  RefPtr<nsWatcherWindowEnumerator> enumerator =
+      new nsWatcherWindowEnumerator(this);
+  enumerator.forget(aResult);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::GetNewPrompter(mozIDOMWindowProxy* aParent,
+                                nsIPrompt** aResult) {
+  // This is for backwards compat only. Callers should just use the prompt
+  // service directly.
+  nsresult rv;
+  nsCOMPtr<nsIPromptFactory> factory =
+      do_GetService("@mozilla.org/prompter;1", &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return factory->GetPrompt(aParent, NS_GET_IID(nsIPrompt),
+                            reinterpret_cast<void**>(aResult));
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::GetNewAuthPrompter(mozIDOMWindowProxy* aParent,
+                                    nsIAuthPrompt** aResult) {
+  // This is for backwards compat only. Callers should just use the prompt
+  // service directly.
+  nsresult rv;
+  nsCOMPtr<nsIPromptFactory> factory =
+      do_GetService("@mozilla.org/prompter;1", &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return factory->GetPrompt(aParent, NS_GET_IID(nsIAuthPrompt),
+                            reinterpret_cast<void**>(aResult));
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::GetPrompt(mozIDOMWindowProxy* aParent, const nsIID& aIID,
+                           void** aResult) {
+  // This is for backwards compat only. Callers should just use the prompt
+  // service directly.
+  nsresult rv;
+  nsCOMPtr<nsIPromptFactory> factory =
+      do_GetService("@mozilla.org/prompter;1", &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = factory->GetPrompt(aParent, aIID, aResult);
+
+  // Allow for an embedding implementation to not support nsIAuthPrompt2.
+  if (rv == NS_NOINTERFACE && aIID.Equals(NS_GET_IID(nsIAuthPrompt2))) {
+    nsCOMPtr<nsIAuthPrompt> oldPrompt;
+    rv = factory->GetPrompt(aParent, NS_GET_IID(nsIAuthPrompt),
+                            getter_AddRefs(oldPrompt));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    NS_WrapAuthPrompt(oldPrompt, reinterpret_cast<nsIAuthPrompt2**>(aResult));
+    if (!*aResult) {
+      rv = NS_ERROR_NOT_AVAILABLE;
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::SetWindowCreator(nsIWindowCreator* aCreator) {
+  mWindowCreator = aCreator;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::HasWindowCreator(bool* aResult) {
+  *aResult = mWindowCreator;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::GetActiveWindow(mozIDOMWindowProxy** aActiveWindow) {
+  *aActiveWindow = nullptr;
+  nsFocusManager* fm = nsFocusManager::GetFocusManager();
+  if (fm) {
+    return fm->GetActiveWindow(aActiveWindow);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::AddWindow(mozIDOMWindowProxy* aWindow,
+                           nsIWebBrowserChrome* aChrome) {
+  if (!aWindow) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  {
+    nsWatcherWindowEntry* info;
+    MutexAutoLock lock(mListLock);
+
+    // if we already have an entry for this window, adjust
+    // its chrome mapping and return
+    info = FindWindowEntry(aWindow);
+    if (info) {
+      nsCOMPtr<nsISupportsWeakReference> supportsweak(
+          do_QueryInterface(aChrome));
+      if (supportsweak) {
+        supportsweak->GetWeakReference(getter_AddRefs(info->mChromeWeak));
+      } else {
+        info->mChrome = aChrome;
+        info->mChromeWeak = nullptr;
+      }
+      return NS_OK;
+    }
+
+    // create a window info struct and add it to the list of windows
+    info = new nsWatcherWindowEntry(aWindow, aChrome);
+    if (!info) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    if (mOldestWindow) {
+      info->InsertAfter(mOldestWindow->mOlder);
+    } else {
+      mOldestWindow = info;
+    }
+  }  // leave the mListLock
+
+  // a window being added to us signifies a newly opened window.
+  // send notifications.
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (!os) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsISupports> domwin(do_QueryInterface(aWindow));
+  return os->NotifyObservers(domwin, "domwindowopened", nullptr);
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::RemoveWindow(mozIDOMWindowProxy* aWindow) {
+  // find the corresponding nsWatcherWindowEntry, remove it
+
+  if (!aWindow) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsWatcherWindowEntry* info = FindWindowEntry(aWindow);
+  if (info) {
+    RemoveWindow(info);
+    return NS_OK;
+  }
+  NS_WARNING("requested removal of nonexistent window");
+  return NS_ERROR_INVALID_ARG;
+}
+
+nsWatcherWindowEntry* nsWindowWatcher::FindWindowEntry(
+    mozIDOMWindowProxy* aWindow) {
+  // find the corresponding nsWatcherWindowEntry
+  nsWatcherWindowEntry* info;
+  nsWatcherWindowEntry* listEnd;
+
+  info = mOldestWindow;
+  listEnd = nullptr;
+  while (info != listEnd) {
+    if (info->mWindow == aWindow) {
+      return info;
+    }
+    info = info->mYounger;
+    listEnd = mOldestWindow;
+  }
+  return nullptr;
+}
+
+nsresult nsWindowWatcher::RemoveWindow(nsWatcherWindowEntry* aInfo) {
+  uint32_t count = mEnumeratorList.Length();
+
+  {
+    // notify the enumerators
+    MutexAutoLock lock(mListLock);
+    for (uint32_t ctr = 0; ctr < count; ++ctr) {
+      mEnumeratorList[ctr]->WindowRemoved(aInfo);
+    }
+
+    // remove the element from the list
+    if (aInfo == mOldestWindow) {
+      mOldestWindow =
+          aInfo->mYounger == mOldestWindow ? nullptr : aInfo->mYounger;
+    }
+    aInfo->Unlink();
+  }
+
+  // a window being removed from us signifies a newly closed window.
+  // send notifications.
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    nsCOMPtr<nsISupports> domwin(do_QueryInterface(aInfo->mWindow));
+    os->NotifyObservers(domwin, "domwindowclosed", nullptr);
+  }
+
+  delete aInfo;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::GetChromeForWindow(mozIDOMWindowProxy* aWindow,
+                                    nsIWebBrowserChrome** aResult) {
+  if (!aWindow || !aResult) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  *aResult = nullptr;
+
+  MutexAutoLock lock(mListLock);
+  nsWatcherWindowEntry* info = FindWindowEntry(aWindow);
+  if (info) {
+    if (info->mChromeWeak) {
+      return info->mChromeWeak->QueryReferent(
+          NS_GET_IID(nsIWebBrowserChrome), reinterpret_cast<void**>(aResult));
+    }
+    *aResult = info->mChrome;
+    NS_IF_ADDREF(*aResult);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowWatcher::GetWindowByName(const nsAString& aTargetName,
+                                 mozIDOMWindowProxy** aResult) {
+  if (!aResult) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  *aResult = nullptr;
+
+  // We won't be able to find any windows with a special or empty name.
+  if (aTargetName.IsEmpty() || nsContentUtils::IsSpecialName(aTargetName)) {
+    return NS_OK;
+  }
+
+  // Search each toplevel in the chrome BrowsingContextGroup for a window with
+  // the given name.
+  for (const RefPtr<BrowsingContext>& toplevel :
+       BrowsingContextGroup::GetChromeGroup()->Toplevels()) {
+    BrowsingContext* context =
+        toplevel->FindWithNameInSubtree(aTargetName, nullptr);
+    if (context) {
+      *aResult = do_AddRef(context->GetDOMWindow()).take();
+      MOZ_ASSERT(*aResult);
+      return NS_OK;
+    }
+  }
+
+  return NS_OK;
+}
+
+bool nsWindowWatcher::AddEnumerator(nsWatcherWindowEnumerator* aEnumerator) {
+  // (requires a lock; assumes it's called by someone holding the lock)
+  // XXX(Bug 1631371) Check if this should use a fallible operation as it
+  // pretended earlier, or change the return type to void.
+  mEnumeratorList.AppendElement(aEnumerator);
+  return true;
+}
+
+bool nsWindowWatcher::RemoveEnumerator(nsWatcherWindowEnumerator* aEnumerator) {
+  // (requires a lock; assumes it's called by someone holding the lock)
+  return mEnumeratorList.RemoveElement(aEnumerator);
+}
+
+nsresult nsWindowWatcher::URIfromURL(const nsACString& aURL,
+                                     mozIDOMWindowProxy* aParent,
+                                     nsIURI** aURI) {
+  // Build the URI relative to the entry global.
+  nsCOMPtr<nsPIDOMWindowInner> baseWindow = do_QueryInterface(GetEntryGlobal());
+
+  // failing that, build it relative to the parent window, if possible
+  if (!baseWindow && aParent) {
+    baseWindow = nsPIDOMWindowOuter::From(aParent)->GetCurrentInnerWindow();
+  }
+
+  // failing that, use the given URL unmodified. It had better not be relative.
+
+  nsIURI* baseURI = nullptr;
+
+  // get baseWindow's document URI
+  if (baseWindow) {
+    if (Document* doc = baseWindow->GetDoc()) {
+      baseURI = doc->GetDocBaseURI();
+    }
+  }
+
+  // build and return the absolute URI
+  return NS_NewURI(aURI, aURL, nullptr, baseURI);
+}
+
+// static
+bool nsWindowWatcher::ShouldOpenPopup(const WindowFeatures& aFeatures) {
+  if (aFeatures.IsEmpty()) {
+    return false;
+  }
+
+  // NOTE: This is different than chrome-only "popup" feature that is handled
+  //       in nsWindowWatcher::CalculateChromeFlagsForSystem.
+  if (aFeatures.Exists("popup")) {
+    return aFeatures.GetBool("popup");
+  }
+
+  if (!aFeatures.GetBoolWithDefault("location", false) &&
+      !aFeatures.GetBoolWithDefault("toolbar", false)) {
+    return true;
+  }
+
+  if (!aFeatures.GetBoolWithDefault("menubar", false)) {
+    return true;
+  }
+
+  if (!aFeatures.GetBoolWithDefault("resizable", true)) {
+    return true;
+  }
+
+  if (!aFeatures.GetBoolWithDefault("scrollbars", false)) {
+    return true;
+  }
+
+  if (!aFeatures.GetBoolWithDefault("status", false)) {
+    return true;
+  }
+
+  return false;
+}
+
+/**
+ * Calculate the chrome bitmask from a string list of features requested
+ * from a child process. The feature string can only control whether to open a
+ * new tab or a new popup.
+ * @param aFeatures a string containing a list of named features
+ * @param aIsPopupRequested an out parameter that indicates whether a popup
+ *        is requested by aFeatures
+ * @return the chrome bitmask
+ */
+// static
+uint32_t nsWindowWatcher::CalculateChromeFlagsForContent(
+    const WindowFeatures& aFeatures,
+    const mozilla::dom::UserActivation::Modifiers& aModifiers,
+    bool* aIsPopupRequested) {
+  if (aFeatures.IsEmpty() || !ShouldOpenPopup(aFeatures)) {
+    // Open the current/new tab in the current/new window
+    // (depends on browser.link.open_newwindow).
+    return nsIWebBrowserChrome::CHROME_ALL;
+  }
+
+  int32_t unused;
+  if (IsWindowOpenLocationModified(aModifiers, &unused)) {
+    // If modifier keys are held when `window.open` is called, open a new
+    // foreground/background tab in the current window, or open a new tab in a
+    // new window, depending on the modifiers combination.
+    return nsIWebBrowserChrome::CHROME_ALL;
+  }
+
+  // Open a minimal popup.
+  *aIsPopupRequested = true;
+  return nsIWebBrowserChrome::CHROME_MINIMAL_POPUP;
+}
+
+/**
+ * Calculate the chrome bitmask from a string list of features for a new
+ * privileged window.
+ * @param aFeatures a string containing a list of named chrome features
+ * @param aDialog affects the assumptions made about unnamed features
+ * @param aChromeURL true if the window is being sent to a chrome:// URL
+ * @return the chrome bitmask
+ */
+// static
+uint32_t nsWindowWatcher::CalculateChromeFlagsForSystem(
+    const WindowFeatures& aFeatures, bool aDialog, bool aChromeURL) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(nsContentUtils::LegacyIsCallerChromeOrNativeCode());
+
+  uint32_t chromeFlags = 0;
+
+  // The features string is made void by OpenWindowInternal
+  // if nullptr was originally passed as the features string.
+  if (aFeatures.IsEmpty()) {
+    chromeFlags = nsIWebBrowserChrome::CHROME_ALL;
+    if (aDialog) {
+      chromeFlags |= nsIWebBrowserChrome::CHROME_OPENAS_DIALOG |
+                     nsIWebBrowserChrome::CHROME_OPENAS_CHROME;
+    }
+  } else {
+    chromeFlags = nsIWebBrowserChrome::CHROME_WINDOW_BORDERS;
+  }
+
+  /* This function has become complicated since browser windows and
+     dialogs diverged. The difference is, browser windows assume all
+     chrome not explicitly mentioned is off, if the features string
+     is not null. Exceptions are some OS border chrome new with Mozilla.
+     Dialogs interpret a (mostly) empty features string to mean
+     "OS's choice," and also support an "all" flag explicitly disallowed
+     in the standards-compliant window.(normal)open. */
+
+  bool presenceFlag = false;
+  if (aDialog && aFeatures.GetBoolWithDefault("all", false, &presenceFlag)) {
+    chromeFlags = nsIWebBrowserChrome::CHROME_ALL;
+  }
+
+  /* Next, allow explicitly named options to override the initial settings */
+  if (aFeatures.GetBoolWithDefault("titlebar", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_TITLEBAR;
+  }
+  if (aFeatures.GetBoolWithDefault("close", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_WINDOW_CLOSE;
+  }
+  if (aFeatures.GetBoolWithDefault("toolbar", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_TOOLBAR;
+  }
+  if (aFeatures.GetBoolWithDefault("location", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_LOCATIONBAR;
+  }
+  if (aFeatures.GetBoolWithDefault("personalbar", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_PERSONAL_TOOLBAR;
+  }
+  if (aFeatures.GetBoolWithDefault("status", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_STATUSBAR;
+  }
+  if (aFeatures.GetBoolWithDefault("menubar", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_MENUBAR;
+  }
+  if (aFeatures.GetBoolWithDefault("resizable", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_WINDOW_RESIZE;
+  }
+  if (aFeatures.GetBoolWithDefault("minimizable", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_WINDOW_MINIMIZE;
+  }
+  if (aFeatures.GetBoolWithDefault("scrollbars", true, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_SCROLLBARS;
+  }
+
+  // Determine whether the window is a private browsing window
+  if (aFeatures.GetBoolWithDefault("private", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW;
+  }
+  if (aFeatures.GetBoolWithDefault("non-private", false, &presenceFlag)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_NON_PRIVATE_WINDOW;
+  }
+
+  // Determine whether the window should have remote tabs.
+  bool remote = BrowserTabsRemoteAutostart();
+
+  if (remote) {
+    remote = !aFeatures.GetBoolWithDefault("non-remote", false, &presenceFlag);
+  } else {
+    remote = aFeatures.GetBoolWithDefault("remote", false, &presenceFlag);
+  }
+
+  if (remote) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_REMOTE_WINDOW;
+  }
+
+  // Determine whether the window should have remote subframes
+  bool fission = FissionAutostart();
+
+  if (fission) {
+    fission =
+        !aFeatures.GetBoolWithDefault("non-fission", false, &presenceFlag);
+  } else {
+    fission = aFeatures.GetBoolWithDefault("fission", false, &presenceFlag);
+  }
+
+  if (fission) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_FISSION_WINDOW;
+  }
+
+  /* OK.
+     Normal browser windows, in spite of a stated pattern of turning off
+     all chrome not mentioned explicitly, will want the new OS chrome (window
+     borders, titlebars, closebox) on, unless explicitly turned off.
+     Dialogs, on the other hand, take the absence of any explicit settings
+     to mean "OS' choice." */
+
+  // default titlebar and closebox to "on," if not mentioned at all
+  if (!aFeatures.Exists("titlebar")) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_TITLEBAR;
+  }
+  if (!aFeatures.Exists("close")) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_WINDOW_CLOSE;
+  }
+
+  if (aDialog && !aFeatures.IsEmpty() && !presenceFlag) {
+    chromeFlags = nsIWebBrowserChrome::CHROME_DEFAULT;
+  }
+
+  /* Finally, once all the above normal chrome has been divined, deal
+     with the features that are more operating hints than appearance
+     instructions. (Note modality implies dependence.) */
+
+  if (aFeatures.GetBoolWithDefault("alwayslowered", false) ||
+      aFeatures.GetBoolWithDefault("z-lock", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_WINDOW_LOWERED;
+  } else if (aFeatures.GetBoolWithDefault("alwaysraised", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_WINDOW_RAISED;
+  }
+
+  if (aFeatures.GetBoolWithDefault("suppressanimation", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_SUPPRESS_ANIMATION;
+  }
+  if (aFeatures.GetBoolWithDefault("alwaysontop", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_ALWAYS_ON_TOP;
+  }
+  if (aFeatures.GetBoolWithDefault("chrome", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_OPENAS_CHROME;
+  }
+  if (aFeatures.GetBoolWithDefault("extrachrome", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_EXTRA;
+  }
+  if (aFeatures.GetBoolWithDefault("centerscreen", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_CENTER_SCREEN;
+  }
+  if (aFeatures.GetBoolWithDefault("dependent", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_DEPENDENT;
+  }
+  if (aFeatures.GetBoolWithDefault("modal", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_MODAL |
+                   nsIWebBrowserChrome::CHROME_DEPENDENT;
+  }
+  if (aFeatures.GetBoolWithDefault("dialog", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_OPENAS_DIALOG;
+  }
+  if (aFeatures.GetBoolWithDefault("alert", false)) {
+    chromeFlags |= nsIWebBrowserChrome::CHROME_ALERT;
+  }
+
+  /* dialogs need to have the last word. assume dialogs are dialogs,
+     and opened as chrome, unless explicitly told otherwise. */
+  if (aDialog) {
+    if (!aFeatures.Exists("dialog")) {
+      chromeFlags |= nsIWebBrowserChrome::CHROME_OPENAS_DIALOG;
+    }
+    if (!aFeatures.Exists("chrome")) {
+      chromeFlags |= nsIWebBrowserChrome::CHROME_OPENAS_CHROME;
+    }
+  }
+
+  return chromeFlags;
+}
+
+// public static
+bool nsWindowWatcher::HaveSpecifiedSize(const WindowFeatures& features) {
+  return CalcSizeSpec(features, false, CSSToDesktopScale()).SizeSpecified();
+}
+
+// static
+SizeSpec CalcSizeSpec(const WindowFeatures& aFeatures, bool aHasChromeParent,
+                      CSSToDesktopScale aCSSToDesktopScale) {
+  SizeSpec result;
+  // https://drafts.csswg.org/cssom-view/#set-up-browsing-context-features
+  // To set up browsing context features for a browsing context `target` given
+  // a map `tokenizedFeatures`:
+
+  // Step 1. Let `x` be null.
+  // (implicit)
+
+  // Step 2. Let `y` be null.
+  // (implicit)
+
+  // Step 3. Let `width` be null.
+  // (implicit)
+
+  // Step 4. Let `height` be null.
+  // (implicit)
+
+  // Step 5. If `tokenizedFeatures["left"]` exists:
+  if (aFeatures.Exists("left")) {
+    // Step 5.1. Set `x` to the result of invoking the rules for parsing
+    // integers on `tokenizedFeatures["left"]`.
+    //
+    // Step 5.2. If `x` is an error, set `x` to 0.
+    int32_t x = aFeatures.GetInt("left");
+
+    // Step 5.3. Optionally, clamp `x` in a user-agent-defined manner so that
+    // the window does not move outside the Web-exposed available screen area.
+    // (done later)
+
+    // Step 5.4. Optionally, move `target`’s window such that the window’s
+    // left edge is at the horizontal coordinate `x` relative to the left edge
+    // of the Web-exposed screen area, measured in CSS pixels of target.
+    // The positive axis is rightward.
+    result.mLeft.emplace((CSSCoord(x) * aCSSToDesktopScale).Rounded());
+  }
+
+  // Step 6. If `tokenizedFeatures["top"]` exists:
+  if (aFeatures.Exists("top")) {
+    // Step 6.1. Set `y` to the result of invoking the rules for parsing
+    // integers on `tokenizedFeatures["top"]`.
+    //
+    // Step 6.2. If `y` is an error, set `y` to 0.
+    int32_t y = aFeatures.GetInt("top");
+
+    // Step 6.3. Optionally, clamp `y` in a user-agent-defined manner so that
+    // the window does not move outside the Web-exposed available screen area.
+    // (done later)
+
+    // Step 6.4. Optionally, move `target`’s window such that the window’s top
+    // edge is at the vertical coordinate `y` relative to the top edge of the
+    // Web-exposed screen area, measured in CSS pixels of target. The positive
+    // axis is downward.
+    result.mTop.emplace((CSSCoord(y) * aCSSToDesktopScale).Rounded());
+  }
+
+  // Non-standard extension.
+  // Not exposed to web content.
+  if (aHasChromeParent && aFeatures.Exists("outerwidth")) {
+    int32_t width = aFeatures.GetInt("outerwidth");
+    if (width) {
+      result.mOuterWidth.emplace(width);
+    }
+  }
+
+  if (result.mOuterWidth.isNothing()) {
+    // Step 7. If `tokenizedFeatures["width"]` exists:
+    if (aFeatures.Exists("width")) {
+      // Step 7.1. Set `width` to the result of invoking the rules for parsing
+      // integers on `tokenizedFeatures["width"]`.
+      //
+      // Step 7.2. If `width` is an error, set `width` to 0.
+      int32_t width = aFeatures.GetInt("width");
+
+      // Step 7.3. If `width` is not 0:
+      if (width) {
+        // Step 7.3.1. Optionally, clamp `width` in a user-agent-defined manner
+        // so that the window does not get too small or bigger than the
+        // Web-exposed available screen area.
+        // (done later)
+
+        // Step 7.3.2. Optionally, size `target`’s window by moving its right
+        // edge such that the distance between the left and right edges of the
+        // viewport are `width` CSS pixels of target.
+        result.mInnerWidth.emplace(width);
+
+        // Step 7.3.3. Optionally, move target’s window in a user-agent-defined
+        // manner so that it does not grow outside the Web-exposed available
+        // screen area.
+        // (done later)
+      }
+    }
+  }
+
+  // Non-standard extension.
+  // Not exposed to web content.
+  if (aHasChromeParent && aFeatures.Exists("outerheight")) {
+    int32_t height = aFeatures.GetInt("outerheight");
+    if (height) {
+      result.mOuterHeight.emplace(height);
+    }
+  }
+
+  if (result.mOuterHeight.isNothing()) {
+    // Step 8. If `tokenizedFeatures["height"]` exists:
+    if (aFeatures.Exists("height")) {
+      // Step 8.1. Set `height` to the result of invoking the rules for parsing
+      // integers on `tokenizedFeatures["height"]`.
+      //
+      // Step 8.2. If `height` is an error, set `height` to 0.
+      int32_t height = aFeatures.GetInt("height");
+
+      // Step 8.3. If `height` is not 0:
+      if (height) {
+        // Step 8.3.1. Optionally, clamp `height` in a user-agent-defined manner
+        // so that the window does not get too small or bigger than the
+        // Web-exposed available screen area.
+        // (done later)
+
+        // Step 8.3.2. Optionally, size `target`’s window by moving its bottom
+        // edge such that the distance between the top and bottom edges of the
+        // viewport are `height` CSS pixels of target.
+        result.mInnerHeight.emplace(height);
+
+        // Step 8.3.3. Optionally, move target’s window in a user-agent-defined
+        // manner so that it does not grow outside the Web-exposed available
+        // screen area.
+        // (done later)
+      }
+    }
+  }
+
+  // NOTE: The value is handled only on chrome-priv code.
+  // See nsWindowWatcher::SizeOpenedWindow.
+  result.mLockAspectRatio =
+      aFeatures.GetBoolWithDefault("lockaspectratio", false);
+  return result;
+}
+
+/* Size and position a new window according to aSizeSpec. This method
+   is assumed to be called after the window has already been given
+   a default position and size; thus its current position and size are
+   accurate defaults. The new window is made visible at method end.
+   @param aTreeOwner
+          The top-level nsIDocShellTreeOwner of the newly opened window.
+   @param aParent
+          The parent window, used to do security checks.
+   @param aIsCallerChrome
+          True if the code requesting the new window is privileged.
+   @param aSizeSpec
+          The size that the new window should be.
+*/
+static void SizeOpenedWindow(nsIDocShellTreeOwner* aTreeOwner,
+                             mozIDOMWindowProxy* aParent, bool aIsCallerChrome,
+                             const SizeSpec& aSizeSpec) {
+  // We should only be sizing top-level windows if we're in the parent
+  // process.
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  // get various interfaces for aDocShellItem, used throughout this method
+  nsCOMPtr<nsIBaseWindow> treeOwnerAsWin(do_QueryInterface(aTreeOwner));
+  if (!treeOwnerAsWin) {  // we'll need this to actually size the docshell
+    return;
+  }
+
+  // The current position and size will be unchanged if not specified
+  // (and they fit entirely onscreen). Also, calculate the difference
+  // between chrome and content sizes on aDocShellItem's window.
+  // This latter point becomes important if chrome and content
+  // specifications are mixed in aFeatures, and when bringing the window
+  // back from too far off the right or bottom edges of the screen.
+  DesktopIntCoord left = 0;
+  DesktopIntCoord top = 0;
+  CSSIntCoord width = 0;
+  CSSIntCoord height = 0;
+  // difference between chrome and content size
+  CSSIntCoord chromeWidth = 0;
+  CSSIntCoord chromeHeight = 0;
+  // whether the window size spec refers to chrome or content
+  bool sizeChromeWidth = true;
+  bool sizeChromeHeight = true;
+
+  {
+    CSSToLayoutDeviceScale cssToDevScale =
+        treeOwnerAsWin->UnscaledDevicePixelsPerCSSPixel();
+    DesktopToLayoutDeviceScale devToDesktopScale =
+        treeOwnerAsWin->DevicePixelsPerDesktopPixel();
+
+    LayoutDeviceIntRect devPxRect = treeOwnerAsWin->GetPositionAndSize();
+    width = (LayoutDeviceCoord(devPxRect.width) / cssToDevScale).Rounded();
+    height = (LayoutDeviceCoord(devPxRect.height) / cssToDevScale).Rounded();
+    left = (LayoutDeviceCoord(devPxRect.x) / devToDesktopScale).Rounded();
+    top = (LayoutDeviceCoord(devPxRect.y) / devToDesktopScale).Rounded();
+
+    LayoutDeviceIntSize contentSize;
+    bool hasPrimaryContent = false;
+    aTreeOwner->GetHasPrimaryContent(&hasPrimaryContent);
+    if (hasPrimaryContent) {
+      aTreeOwner->GetPrimaryContentSize(&contentSize.width,
+                                        &contentSize.height);
+    } else {
+      aTreeOwner->GetRootShellSize(&contentSize.width, &contentSize.height);
+    }
+
+    CSSIntSize contentSizeCSS = RoundedToInt(contentSize / cssToDevScale);
+    chromeWidth = width - contentSizeCSS.width;
+    chromeHeight = height - contentSizeCSS.height;
+  }
+
+  // Set up left/top
+  if (aSizeSpec.mLeft) {
+    left = *aSizeSpec.mLeft;
+  }
+
+  if (aSizeSpec.mTop) {
+    top = *aSizeSpec.mTop;
+  }
+
+  // Set up width
+  if (aSizeSpec.mOuterWidth) {
+    width = *aSizeSpec.mOuterWidth;
+  } else if (aSizeSpec.mInnerWidth) {
+    sizeChromeWidth = false;
+    width = *aSizeSpec.mInnerWidth;
+  }
+
+  // Set up height
+  if (aSizeSpec.mOuterHeight) {
+    height = *aSizeSpec.mOuterHeight;
+  } else if (aSizeSpec.mInnerHeight) {
+    sizeChromeHeight = false;
+    height = *aSizeSpec.mInnerHeight;
+  }
+
+  bool positionSpecified = aSizeSpec.PositionSpecified();
+
+  // Check security state for use in determining window dimensions
+  bool enabled = false;
+  if (aIsCallerChrome) {
+    // Only enable special privileges for chrome when chrome calls
+    // open() on a chrome window
+    enabled = !aParent || nsGlobalWindowOuter::Cast(aParent)->IsChromeWindow();
+  }
+
+  const CSSIntCoord extraWidth = sizeChromeWidth ? CSSIntCoord(0) : chromeWidth;
+  const CSSIntCoord extraHeight =
+      sizeChromeHeight ? CSSIntCoord(0) : chromeHeight;
+
+  if (!enabled) {
+    // Security check failed.  Ensure all args meet minimum reqs.
+
+    int32_t oldTop = top, oldLeft = left;
+
+    // We'll also need the screen dimensions
+    nsCOMPtr<nsIScreen> screen;
+    nsCOMPtr<nsIScreenManager> screenMgr(
+        do_GetService("@mozilla.org/gfx/screenmanager;1"));
+    if (screenMgr) {
+      // XXX width, height are in CSS rather than desktop pixels here.
+      screenMgr->ScreenForRect(left, top, width, height,
+                               getter_AddRefs(screen));
+    }
+    if (screen) {
+      CSSIntCoord winWidth = width + extraWidth;
+      CSSIntCoord winHeight = height + extraHeight;
+
+      auto screenCssToDesktopScale = screen->GetCSSToDesktopScale();
+
+      const DesktopIntRect screenDesktopRect = screen->GetAvailRectDisplayPix();
+      // Get screen dimensions (in CSS pixels)
+      const CSSSize screenCssSize =
+          screenDesktopRect.Size() / screenCssToDesktopScale;
+
+      if (aSizeSpec.SizeSpecified()) {
+        if (!nsContentUtils::ShouldResistFingerprinting(
+                "When RFP is enabled, we unconditionally round new window "
+                "sizes. The code paths that create new windows are "
+                "complicated, and this is a conservative behavior to avoid "
+                "exempting something that shouldn't be. It also presents a "
+                "uniform behavior for something that's very browser-related.",
+                RFPTarget::RoundWindowSize)) {
+          /* Unlike position, force size out-of-bounds check only if
+             size actually was specified. Otherwise, intrinsically sized
+             windows are broken. */
+          if (height < 100) {
+            height = 100;
+            winHeight = height + extraHeight;
+          }
+          if (winHeight > screenCssSize.height) {
+            height = static_cast<int32_t>(screenCssSize.height - extraHeight);
+          }
+          if (width < 100) {
+            width = 100;
+            winWidth = width + extraWidth;
+          }
+          if (winWidth > screenCssSize.width) {
+            width = static_cast<int32_t>(screenCssSize.width - extraWidth);
+          }
+        } else {
+          int32_t targetContentWidth = 0;
+          int32_t targetContentHeight = 0;
+
+          nsContentUtils::CalcRoundedWindowSizeForResistingFingerprinting(
+              chromeWidth, chromeHeight, screenCssSize.width,
+              screenCssSize.height, width, height, sizeChromeWidth,
+              sizeChromeHeight, &targetContentWidth, &targetContentHeight);
+
+          if (aSizeSpec.mInnerWidth || aSizeSpec.mOuterWidth) {
+            width = targetContentWidth;
+            winWidth = width + extraWidth;
+          }
+
+          if (aSizeSpec.mInnerHeight || aSizeSpec.mOuterHeight) {
+            height = targetContentHeight;
+            winHeight = height + extraHeight;
+          }
+        }
+      }
+
+      const DesktopIntCoord desktopWinWidth =
+          (CSSCoord(winWidth) * screenCssToDesktopScale).Rounded();
+      const DesktopIntCoord desktopWinHeight =
+          (CSSCoord(winHeight) * screenCssToDesktopScale).Rounded();
+      CheckedInt<int32_t> leftPlusWinWidth = int32_t(left);
+      leftPlusWinWidth += int32_t(desktopWinWidth);
+      if (!leftPlusWinWidth.isValid() ||
+          leftPlusWinWidth.value() > screenDesktopRect.XMost()) {
+        left = screenDesktopRect.XMost() - desktopWinWidth;
+      }
+      if (left < screenDesktopRect.x) {
+        left = screenDesktopRect.x;
+      }
+
+      CheckedInt<int32_t> topPlusWinHeight = int32_t(top);
+      topPlusWinHeight += int32_t(desktopWinHeight);
+      if (!topPlusWinHeight.isValid() ||
+          topPlusWinHeight.value() > screenDesktopRect.YMost()) {
+        top = screenDesktopRect.YMost() - desktopWinHeight;
+      }
+      if (top < screenDesktopRect.y) {
+        top = screenDesktopRect.y;
+      }
+
+      if (top != oldTop || left != oldLeft) {
+        positionSpecified = true;
+      }
+    }
+  }
+
+  // size and position the window
+
+  if (positionSpecified) {
+    treeOwnerAsWin->SetPositionDesktopPix(left, top);
+  }
+
+  if (aSizeSpec.SizeSpecified()) {
+    const CSSToLayoutDeviceScale scale =
+        treeOwnerAsWin->UnscaledDevicePixelsPerCSSPixel();
+
+    /* Prefer to trust the interfaces, which think in terms of pure
+       chrome or content sizes. If we have a mix, use the chrome size
+       adjusted by the chrome/content differences calculated earlier. */
+    if (!sizeChromeWidth && !sizeChromeHeight) {
+      const LayoutDeviceIntCoord widthDevPx =
+          (CSSCoord(width) * scale).Rounded();
+      const LayoutDeviceIntCoord heightDevPx =
+          (CSSCoord(height) * scale).Rounded();
+      bool hasPrimaryContent = false;
+      aTreeOwner->GetHasPrimaryContent(&hasPrimaryContent);
+      if (hasPrimaryContent) {
+        aTreeOwner->SetPrimaryContentSize(widthDevPx, heightDevPx);
+      } else {
+        aTreeOwner->SetRootShellSize(widthDevPx, heightDevPx);
+      }
+    } else {
+      const LayoutDeviceIntCoord widthDevPx =
+          (CSSCoord(width + extraWidth) * scale).Rounded();
+      const LayoutDeviceIntCoord heightDevPx =
+          (CSSCoord(height + extraHeight) * scale).Rounded();
+      treeOwnerAsWin->SetSize(widthDevPx, heightDevPx, false);
+    }
+  }
+
+  if (aIsCallerChrome) {
+    nsCOMPtr<nsIAppWindow> appWin = do_GetInterface(treeOwnerAsWin);
+    if (appWin && aSizeSpec.mLockAspectRatio) {
+      appWin->LockAspectRatio(true);
+    }
+  }
+
+  treeOwnerAsWin->SetVisibility(true);
+}
+
+/* static */
+bool nsWindowWatcher::IsWindowOpenLocationModified(
+    const mozilla::dom::UserActivation::Modifiers& aModifiers,
+    int32_t* aLocation) {
+  // Perform the subset of BrowserUtils.whereToOpenLink in
+  // toolkit/modules/BrowserUtils.sys.mjs
+#ifdef XP_MACOSX
+  bool metaKey = aModifiers.IsMeta();
+#else
+  bool metaKey = aModifiers.IsControl();
+#endif
+  bool shiftKey = aModifiers.IsShift();
+  if (metaKey) {
+    if (shiftKey) {
+      *aLocation = nsIBrowserDOMWindow::OPEN_NEWTAB;
+      return true;
+    }
+    *aLocation = nsIBrowserDOMWindow::OPEN_NEWTAB_BACKGROUND;
+    return true;
+  }
+  if (shiftKey) {
+    *aLocation = nsIBrowserDOMWindow::OPEN_NEWWINDOW;
+    return true;
+  }
+
+  return false;
+}
+
+/* static */
+int32_t nsWindowWatcher::GetWindowOpenLocation(
+    nsPIDOMWindowOuter* aParent, uint32_t aChromeFlags,
+    const mozilla::dom::UserActivation::Modifiers& aModifiers,
+    bool aCalledFromJS, bool aIsForPrinting) {
+  // These windows are not actually visible to the user, so we return the thing
+  // that we can always handle.
+  if (aIsForPrinting) {
+    return nsIBrowserDOMWindow::OPEN_PRINT_BROWSER;
+  }
+
+  int32_t modifiedLocation = 0;
+  if (IsWindowOpenLocationModified(aModifiers, &modifiedLocation)) {
+    return modifiedLocation;
+  }
+
+  // Where should we open this?
+  int32_t containerPref;
+  if (NS_FAILED(
+          Preferences::GetInt("browser.link.open_newwindow", &containerPref))) {
+    // We couldn't read the user preference, so fall back on the default.
+    return nsIBrowserDOMWindow::OPEN_NEWTAB;
+  }
+
+  bool isDisabledOpenNewWindow =
+      aParent->GetFullScreen() &&
+      Preferences::GetBool(
+          "browser.link.open_newwindow.disabled_in_fullscreen");
+
+  if (isDisabledOpenNewWindow &&
+      (containerPref == nsIBrowserDOMWindow::OPEN_NEWWINDOW)) {
+    containerPref = nsIBrowserDOMWindow::OPEN_NEWTAB;
+  }
+
+  if (containerPref != nsIBrowserDOMWindow::OPEN_NEWTAB &&
+      containerPref != nsIBrowserDOMWindow::OPEN_CURRENTWINDOW) {
+    // Just open a window normally
+    return nsIBrowserDOMWindow::OPEN_NEWWINDOW;
+  }
+
+  if (aCalledFromJS) {
+    /* Now check our restriction pref.  The restriction pref is a power-user's
+       fine-tuning pref. values:
+       0: no restrictions - divert everything
+       1: don't divert window.open at all
+       2: don't divert window.open with features
+    */
+    int32_t restrictionPref =
+        Preferences::GetInt("browser.link.open_newwindow.restriction", 2);
+    if (restrictionPref < 0 || restrictionPref > 2) {
+      restrictionPref = 2;  // Sane default behavior
+    }
+
+    if (isDisabledOpenNewWindow) {
+      // In browser fullscreen, the window should be opened
+      // in the current window with no features (see bug 803675)
+      restrictionPref = 0;
+    }
+
+    if (restrictionPref == 1) {
+      return nsIBrowserDOMWindow::OPEN_NEWWINDOW;
+    }
+
+    if (restrictionPref == 2) {
+      // Only continue if there is no special chrome flags - with the exception
+      // of the remoteness and private flags, which might have been
+      // automatically flipped by Gecko.
+      int32_t uiChromeFlags = aChromeFlags;
+      uiChromeFlags &= ~(nsIWebBrowserChrome::CHROME_REMOTE_WINDOW |
+                         nsIWebBrowserChrome::CHROME_FISSION_WINDOW |
+                         nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW |
+                         nsIWebBrowserChrome::CHROME_NON_PRIVATE_WINDOW |
+                         nsIWebBrowserChrome::CHROME_PRIVATE_LIFETIME);
+      if (uiChromeFlags != nsIWebBrowserChrome::CHROME_ALL) {
+        return nsIBrowserDOMWindow::OPEN_NEWWINDOW;
+      }
+    }
+  }
+
+  return containerPref;
+}