Adding upstream version 86.0.1.upstream/86.0.1upstream

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

1 files changed, 1304 insertions, 0 deletions

diff --git a/docshell/base/nsDocShellTreeOwner.cpp b/docshell/base/nsDocShellTreeOwner.cpp
new file mode 100644
index 0000000000..ff2b4dca6c
--- /dev/null
+++ b/docshell/base/nsDocShellTreeOwner.cpp
@@ -0,0 +1,1304 @@
+/* -*- 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/. */
+
+// Local Includes
+#include "nsDocShellTreeOwner.h"
+#include "nsWebBrowser.h"
+
+// Helper Classes
+#include "nsContentUtils.h"
+#include "nsSize.h"
+#include "mozilla/ReflowInput.h"
+#include "mozilla/ScopeExit.h"
+#include "nsComponentManagerUtils.h"
+#include "nsString.h"
+#include "nsAtom.h"
+#include "nsReadableUtils.h"
+#include "nsUnicharUtils.h"
+#include "mozilla/LookAndFeel.h"
+
+// Interfaces needed to be included
+#include "nsPresContext.h"
+#include "nsITooltipListener.h"
+#include "nsINode.h"
+#include "Link.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/MouseEvent.h"
+#include "mozilla/dom/SVGTitleElement.h"
+#include "nsIFormControl.h"
+#include "nsIWebNavigation.h"
+#include "nsPIDOMWindow.h"
+#include "nsPIWindowRoot.h"
+#include "nsIWindowWatcher.h"
+#include "nsPIWindowWatcher.h"
+#include "nsIPrompt.h"
+#include "nsIRemoteTab.h"
+#include "nsIBrowserChild.h"
+#include "nsRect.h"
+#include "nsIWebBrowserChromeFocus.h"
+#include "nsIContent.h"
+#include "nsServiceManagerUtils.h"
+#include "nsViewManager.h"
+#include "nsView.h"
+#include "nsIConstraintValidation.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/EventListenerManager.h"
+#include "mozilla/dom/DragEvent.h"
+#include "mozilla/dom/Event.h"     // for Event
+#include "mozilla/dom/File.h"      // for input type=file
+#include "mozilla/dom/FileList.h"  // for input type=file
+#include "mozilla/dom/LoadURIOptionsBinding.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/TextEvents.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+// A helper routine that navigates the tricky path from a |nsWebBrowser| to
+// a |EventTarget| via the window root and chrome event handler.
+static nsresult GetDOMEventTarget(nsWebBrowser* aInBrowser,
+                                  EventTarget** aTarget) {
+  if (!aInBrowser) {
+    return NS_ERROR_INVALID_POINTER;
+  }
+
+  nsCOMPtr<mozIDOMWindowProxy> domWindow;
+  aInBrowser->GetContentDOMWindow(getter_AddRefs(domWindow));
+  if (!domWindow) {
+    return NS_ERROR_FAILURE;
+  }
+
+  auto* outerWindow = nsPIDOMWindowOuter::From(domWindow);
+  nsPIDOMWindowOuter* rootWindow = outerWindow->GetPrivateRoot();
+  NS_ENSURE_TRUE(rootWindow, NS_ERROR_FAILURE);
+  nsCOMPtr<EventTarget> target = rootWindow->GetChromeEventHandler();
+  NS_ENSURE_TRUE(target, NS_ERROR_FAILURE);
+  target.forget(aTarget);
+
+  return NS_OK;
+}
+
+nsDocShellTreeOwner::nsDocShellTreeOwner()
+    : mWebBrowser(nullptr),
+      mTreeOwner(nullptr),
+      mPrimaryContentShell(nullptr),
+      mWebBrowserChrome(nullptr),
+      mOwnerWin(nullptr),
+      mOwnerRequestor(nullptr) {}
+
+nsDocShellTreeOwner::~nsDocShellTreeOwner() { RemoveChromeListeners(); }
+
+NS_IMPL_ADDREF(nsDocShellTreeOwner)
+NS_IMPL_RELEASE(nsDocShellTreeOwner)
+
+NS_INTERFACE_MAP_BEGIN(nsDocShellTreeOwner)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDocShellTreeOwner)
+  NS_INTERFACE_MAP_ENTRY(nsIDocShellTreeOwner)
+  NS_INTERFACE_MAP_ENTRY(nsIBaseWindow)
+  NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
+  NS_INTERFACE_MAP_ENTRY(nsIWebProgressListener)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMEventListener)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+NS_INTERFACE_MAP_END
+
+//*****************************************************************************
+// nsDocShellTreeOwner::nsIInterfaceRequestor
+//*****************************************************************************
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetInterface(const nsIID& aIID, void** aSink) {
+  NS_ENSURE_ARG_POINTER(aSink);
+
+  if (NS_SUCCEEDED(QueryInterface(aIID, aSink))) {
+    return NS_OK;
+  }
+
+  if (aIID.Equals(NS_GET_IID(nsIWebBrowserChromeFocus))) {
+    if (mWebBrowserChromeWeak != nullptr) {
+      return mWebBrowserChromeWeak->QueryReferent(aIID, aSink);
+    }
+    return mOwnerWin->QueryInterface(aIID, aSink);
+  }
+
+  if (aIID.Equals(NS_GET_IID(nsIPrompt))) {
+    nsCOMPtr<nsIPrompt> prompt;
+    EnsurePrompter();
+    prompt = mPrompter;
+    if (prompt) {
+      prompt.forget(aSink);
+      return NS_OK;
+    }
+    return NS_NOINTERFACE;
+  }
+
+  if (aIID.Equals(NS_GET_IID(nsIAuthPrompt))) {
+    nsCOMPtr<nsIAuthPrompt> prompt;
+    EnsureAuthPrompter();
+    prompt = mAuthPrompter;
+    if (prompt) {
+      prompt.forget(aSink);
+      return NS_OK;
+    }
+    return NS_NOINTERFACE;
+  }
+
+  nsCOMPtr<nsIInterfaceRequestor> req = GetOwnerRequestor();
+  if (req) {
+    return req->GetInterface(aIID, aSink);
+  }
+
+  return NS_NOINTERFACE;
+}
+
+//*****************************************************************************
+// nsDocShellTreeOwner::nsIDocShellTreeOwner
+//*****************************************************************************
+
+void nsDocShellTreeOwner::EnsurePrompter() {
+  if (mPrompter) {
+    return;
+  }
+
+  nsCOMPtr<nsIWindowWatcher> wwatch(do_GetService(NS_WINDOWWATCHER_CONTRACTID));
+  if (wwatch && mWebBrowser) {
+    nsCOMPtr<mozIDOMWindowProxy> domWindow;
+    mWebBrowser->GetContentDOMWindow(getter_AddRefs(domWindow));
+    if (domWindow) {
+      wwatch->GetNewPrompter(domWindow, getter_AddRefs(mPrompter));
+    }
+  }
+}
+
+void nsDocShellTreeOwner::EnsureAuthPrompter() {
+  if (mAuthPrompter) {
+    return;
+  }
+
+  nsCOMPtr<nsIWindowWatcher> wwatch(do_GetService(NS_WINDOWWATCHER_CONTRACTID));
+  if (wwatch && mWebBrowser) {
+    nsCOMPtr<mozIDOMWindowProxy> domWindow;
+    mWebBrowser->GetContentDOMWindow(getter_AddRefs(domWindow));
+    if (domWindow) {
+      wwatch->GetNewAuthPrompter(domWindow, getter_AddRefs(mAuthPrompter));
+    }
+  }
+}
+
+void nsDocShellTreeOwner::AddToWatcher() {
+  if (mWebBrowser) {
+    nsCOMPtr<mozIDOMWindowProxy> domWindow;
+    mWebBrowser->GetContentDOMWindow(getter_AddRefs(domWindow));
+    if (domWindow) {
+      nsCOMPtr<nsPIWindowWatcher> wwatch(
+          do_GetService(NS_WINDOWWATCHER_CONTRACTID));
+      if (wwatch) {
+        nsCOMPtr<nsIWebBrowserChrome> webBrowserChrome = GetWebBrowserChrome();
+        if (webBrowserChrome) {
+          wwatch->AddWindow(domWindow, webBrowserChrome);
+        }
+      }
+    }
+  }
+}
+
+void nsDocShellTreeOwner::RemoveFromWatcher() {
+  if (mWebBrowser) {
+    nsCOMPtr<mozIDOMWindowProxy> domWindow;
+    mWebBrowser->GetContentDOMWindow(getter_AddRefs(domWindow));
+    if (domWindow) {
+      nsCOMPtr<nsPIWindowWatcher> wwatch(
+          do_GetService(NS_WINDOWWATCHER_CONTRACTID));
+      if (wwatch) {
+        wwatch->RemoveWindow(domWindow);
+      }
+    }
+  }
+}
+
+void nsDocShellTreeOwner::EnsureContentTreeOwner() {
+  if (mContentTreeOwner) {
+    return;
+  }
+
+  mContentTreeOwner = new nsDocShellTreeOwner();
+  nsCOMPtr<nsIWebBrowserChrome> browserChrome = GetWebBrowserChrome();
+  if (browserChrome) {
+    mContentTreeOwner->SetWebBrowserChrome(browserChrome);
+  }
+
+  if (mWebBrowser) {
+    mContentTreeOwner->WebBrowser(mWebBrowser);
+  }
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::ContentShellAdded(nsIDocShellTreeItem* aContentShell,
+                                       bool aPrimary) {
+  if (mTreeOwner) return mTreeOwner->ContentShellAdded(aContentShell, aPrimary);
+
+  EnsureContentTreeOwner();
+  aContentShell->SetTreeOwner(mContentTreeOwner);
+
+  if (aPrimary) {
+    mPrimaryContentShell = aContentShell;
+    mPrimaryRemoteTab = nullptr;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::ContentShellRemoved(nsIDocShellTreeItem* aContentShell) {
+  if (mTreeOwner) {
+    return mTreeOwner->ContentShellRemoved(aContentShell);
+  }
+
+  if (mPrimaryContentShell == aContentShell) {
+    mPrimaryContentShell = nullptr;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetPrimaryContentShell(nsIDocShellTreeItem** aShell) {
+  NS_ENSURE_ARG_POINTER(aShell);
+
+  if (mTreeOwner) {
+    return mTreeOwner->GetPrimaryContentShell(aShell);
+  }
+
+  nsCOMPtr<nsIDocShellTreeItem> shell;
+  if (!mPrimaryRemoteTab) {
+    shell =
+        mPrimaryContentShell ? mPrimaryContentShell : mWebBrowser->mDocShell;
+  }
+  shell.forget(aShell);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::RemoteTabAdded(nsIRemoteTab* aTab, bool aPrimary) {
+  if (mTreeOwner) {
+    return mTreeOwner->RemoteTabAdded(aTab, aPrimary);
+  }
+
+  if (aPrimary) {
+    mPrimaryRemoteTab = aTab;
+    mPrimaryContentShell = nullptr;
+  } else if (mPrimaryRemoteTab == aTab) {
+    mPrimaryRemoteTab = nullptr;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::RemoteTabRemoved(nsIRemoteTab* aTab) {
+  if (mTreeOwner) {
+    return mTreeOwner->RemoteTabRemoved(aTab);
+  }
+
+  if (aTab == mPrimaryRemoteTab) {
+    mPrimaryRemoteTab = nullptr;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetPrimaryRemoteTab(nsIRemoteTab** aTab) {
+  if (mTreeOwner) {
+    return mTreeOwner->GetPrimaryRemoteTab(aTab);
+  }
+
+  nsCOMPtr<nsIRemoteTab> tab = mPrimaryRemoteTab;
+  tab.forget(aTab);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetPrimaryContentSize(int32_t* aWidth, int32_t* aHeight) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetPrimaryContentSize(int32_t aWidth, int32_t aHeight) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetRootShellSize(int32_t* aWidth, int32_t* aHeight) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetRootShellSize(int32_t aWidth, int32_t aHeight) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SizeShellTo(nsIDocShellTreeItem* aShellItem, int32_t aCX,
+                                 int32_t aCY) {
+  nsCOMPtr<nsIWebBrowserChrome> webBrowserChrome = GetWebBrowserChrome();
+
+  NS_ENSURE_STATE(mTreeOwner || webBrowserChrome);
+
+  if (nsCOMPtr<nsIDocShellTreeOwner> treeOwner = mTreeOwner) {
+    return treeOwner->SizeShellTo(aShellItem, aCX, aCY);
+  }
+
+  if (aShellItem == mWebBrowser->mDocShell) {
+    nsCOMPtr<nsIBrowserChild> browserChild =
+        do_QueryInterface(webBrowserChrome);
+    if (browserChild) {
+      // The XUL window to resize is in the parent process, but there we
+      // won't be able to get aShellItem to do the hack in
+      // AppWindow::SizeShellTo, so let's send the width and height of
+      // aShellItem too.
+      nsCOMPtr<nsIBaseWindow> shellAsWin(do_QueryInterface(aShellItem));
+      NS_ENSURE_TRUE(shellAsWin, NS_ERROR_FAILURE);
+
+      int32_t width = 0;
+      int32_t height = 0;
+      shellAsWin->GetSize(&width, &height);
+      return browserChild->RemoteSizeShellTo(aCX, aCY, width, height);
+    }
+    // XXX: this is weird, but we used to call a method here
+    // (webBrowserChrome->SizeBrowserTo()) whose implementations all failed
+    // like this, so...
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  NS_ENSURE_TRUE(aShellItem, NS_ERROR_FAILURE);
+
+  RefPtr<Document> document = aShellItem->GetDocument();
+  NS_ENSURE_TRUE(document, NS_ERROR_FAILURE);
+
+  NS_ENSURE_TRUE(document->GetDocumentElement(), NS_ERROR_FAILURE);
+
+  // Set the preferred Size
+  // XXX
+  NS_ERROR("Implement this");
+  /*
+  Set the preferred size on the aShellItem.
+  */
+
+  RefPtr<nsPresContext> presContext = mWebBrowser->mDocShell->GetPresContext();
+  NS_ENSURE_TRUE(presContext, NS_ERROR_FAILURE);
+
+  RefPtr<PresShell> presShell = presContext->GetPresShell();
+  NS_ENSURE_TRUE(presShell, NS_ERROR_FAILURE);
+
+  NS_ENSURE_SUCCESS(
+      presShell->ResizeReflow(NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE),
+      NS_ERROR_FAILURE);
+
+  // XXX: this is weird, but we used to call a method here
+  // (webBrowserChrome->SizeBrowserTo()) whose implementations all failed like
+  // this, so...
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetPersistence(bool aPersistPosition, bool aPersistSize,
+                                    bool aPersistSizeMode) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetPersistence(bool* aPersistPosition, bool* aPersistSize,
+                                    bool* aPersistSizeMode) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetTabCount(uint32_t* aResult) {
+  if (mTreeOwner) {
+    return mTreeOwner->GetTabCount(aResult);
+  }
+
+  *aResult = 0;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetHasPrimaryContent(bool* aResult) {
+  *aResult = mPrimaryRemoteTab || mPrimaryContentShell;
+  return NS_OK;
+}
+
+//*****************************************************************************
+// nsDocShellTreeOwner::nsIBaseWindow
+//*****************************************************************************
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::InitWindow(nativeWindow aParentNativeWindow,
+                                nsIWidget* aParentWidget, int32_t aX,
+                                int32_t aY, int32_t aCX, int32_t aCY) {
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::Destroy() {
+  nsCOMPtr<nsIWebBrowserChrome> webBrowserChrome = GetWebBrowserChrome();
+  if (webBrowserChrome) {
+    // XXX: this is weird, but we used to call a method here
+    // (webBrowserChrome->DestroyBrowserWindow()) whose implementations all
+    // failed like this, so...
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetUnscaledDevicePixelsPerCSSPixel(double* aScale) {
+  if (mWebBrowser) {
+    return mWebBrowser->GetUnscaledDevicePixelsPerCSSPixel(aScale);
+  }
+
+  *aScale = 1.0;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetDevicePixelsPerDesktopPixel(double* aScale) {
+  if (mWebBrowser) {
+    return mWebBrowser->GetDevicePixelsPerDesktopPixel(aScale);
+  }
+
+  *aScale = 1.0;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetPositionDesktopPix(int32_t aX, int32_t aY) {
+  if (mWebBrowser) {
+    nsresult rv = mWebBrowser->SetPositionDesktopPix(aX, aY);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  double scale = 1.0;
+  GetDevicePixelsPerDesktopPixel(&scale);
+  return SetPosition(NSToIntRound(aX * scale), NSToIntRound(aY * scale));
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetPosition(int32_t aX, int32_t aY) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->SetDimensions(nsIEmbeddingSiteWindow::DIM_FLAGS_POSITION,
+                                   aX, aY, 0, 0);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetPosition(int32_t* aX, int32_t* aY) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->GetDimensions(nsIEmbeddingSiteWindow::DIM_FLAGS_POSITION,
+                                   aX, aY, nullptr, nullptr);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetSize(int32_t aCX, int32_t aCY, bool aRepaint) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->SetDimensions(nsIEmbeddingSiteWindow::DIM_FLAGS_SIZE_OUTER,
+                                   0, 0, aCX, aCY);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetSize(int32_t* aCX, int32_t* aCY) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->GetDimensions(nsIEmbeddingSiteWindow::DIM_FLAGS_SIZE_OUTER,
+                                   nullptr, nullptr, aCX, aCY);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetPositionAndSize(int32_t aX, int32_t aY, int32_t aCX,
+                                        int32_t aCY, uint32_t aFlags) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->SetDimensions(
+        nsIEmbeddingSiteWindow::DIM_FLAGS_SIZE_OUTER |
+            nsIEmbeddingSiteWindow::DIM_FLAGS_POSITION,
+        aX, aY, aCX, aCY);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetPositionAndSize(int32_t* aX, int32_t* aY, int32_t* aCX,
+                                        int32_t* aCY) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->GetDimensions(
+        nsIEmbeddingSiteWindow::DIM_FLAGS_SIZE_OUTER |
+            nsIEmbeddingSiteWindow::DIM_FLAGS_POSITION,
+        aX, aY, aCX, aCY);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::Repaint(bool aForce) { return NS_ERROR_NULL_POINTER; }
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetParentWidget(nsIWidget** aParentWidget) {
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetParentWidget(nsIWidget* aParentWidget) {
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetParentNativeWindow(nativeWindow* aParentNativeWindow) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->GetSiteWindow(aParentNativeWindow);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetParentNativeWindow(nativeWindow aParentNativeWindow) {
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetNativeHandle(nsAString& aNativeHandle) {
+  // the nativeHandle should be accessed from nsIAppWindow
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetVisibility(bool* aVisibility) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->GetVisibility(aVisibility);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetVisibility(bool aVisibility) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->SetVisibility(aVisibility);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetEnabled(bool* aEnabled) {
+  NS_ENSURE_ARG_POINTER(aEnabled);
+  *aEnabled = true;
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetEnabled(bool aEnabled) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetMainWidget(nsIWidget** aMainWidget) {
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetFocus() {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->SetFocus();
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::GetTitle(nsAString& aTitle) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->GetTitle(aTitle);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetTitle(const nsAString& aTitle) {
+  nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin = GetOwnerWin();
+  if (ownerWin) {
+    return ownerWin->SetTitle(aTitle);
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+//*****************************************************************************
+// nsDocShellTreeOwner::nsIWebProgressListener
+//*****************************************************************************
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::OnProgressChange(nsIWebProgress* aProgress,
+                                      nsIRequest* aRequest,
+                                      int32_t aCurSelfProgress,
+                                      int32_t aMaxSelfProgress,
+                                      int32_t aCurTotalProgress,
+                                      int32_t aMaxTotalProgress) {
+  // In the absence of DOM document creation event, this method is the
+  // most convenient place to install the mouse listener on the
+  // DOM document.
+  return AddChromeListeners();
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::OnStateChange(nsIWebProgress* aProgress,
+                                   nsIRequest* aRequest,
+                                   uint32_t aProgressStateFlags,
+                                   nsresult aStatus) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::OnLocationChange(nsIWebProgress* aWebProgress,
+                                      nsIRequest* aRequest, nsIURI* aURI,
+                                      uint32_t aFlags) {
+  if (mChromeTooltipListener && aWebProgress &&
+      !(aFlags & nsIWebProgressListener::LOCATION_CHANGE_SAME_DOCUMENT) &&
+      mChromeTooltipListener->WebProgressShowedTooltip(aWebProgress)) {
+    mChromeTooltipListener->HideTooltip();
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::OnStatusChange(nsIWebProgress* aWebProgress,
+                                    nsIRequest* aRequest, nsresult aStatus,
+                                    const char16_t* aMessage) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::OnSecurityChange(nsIWebProgress* aWebProgress,
+                                      nsIRequest* aRequest, uint32_t aState) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::OnContentBlockingEvent(nsIWebProgress* aWebProgress,
+                                            nsIRequest* aRequest,
+                                            uint32_t aEvent) {
+  return NS_OK;
+}
+
+//*****************************************************************************
+// nsDocShellTreeOwner: Accessors
+//*****************************************************************************
+
+void nsDocShellTreeOwner::WebBrowser(nsWebBrowser* aWebBrowser) {
+  if (!aWebBrowser) {
+    RemoveChromeListeners();
+  }
+  if (aWebBrowser != mWebBrowser) {
+    mPrompter = nullptr;
+    mAuthPrompter = nullptr;
+  }
+
+  mWebBrowser = aWebBrowser;
+
+  if (mContentTreeOwner) {
+    mContentTreeOwner->WebBrowser(aWebBrowser);
+    if (!aWebBrowser) {
+      mContentTreeOwner = nullptr;
+    }
+  }
+}
+
+nsWebBrowser* nsDocShellTreeOwner::WebBrowser() { return mWebBrowser; }
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetTreeOwner(nsIDocShellTreeOwner* aTreeOwner) {
+  if (aTreeOwner) {
+    nsCOMPtr<nsIWebBrowserChrome> webBrowserChrome(do_GetInterface(aTreeOwner));
+    NS_ENSURE_TRUE(webBrowserChrome, NS_ERROR_INVALID_ARG);
+    NS_ENSURE_SUCCESS(SetWebBrowserChrome(webBrowserChrome),
+                      NS_ERROR_INVALID_ARG);
+    mTreeOwner = aTreeOwner;
+  } else {
+    mTreeOwner = nullptr;
+    nsCOMPtr<nsIWebBrowserChrome> webBrowserChrome = GetWebBrowserChrome();
+    if (!webBrowserChrome) {
+      NS_ENSURE_SUCCESS(SetWebBrowserChrome(nullptr), NS_ERROR_FAILURE);
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::SetWebBrowserChrome(
+    nsIWebBrowserChrome* aWebBrowserChrome) {
+  if (!aWebBrowserChrome) {
+    mWebBrowserChrome = nullptr;
+    mOwnerWin = nullptr;
+    mOwnerRequestor = nullptr;
+    mWebBrowserChromeWeak = nullptr;
+  } else {
+    nsCOMPtr<nsISupportsWeakReference> supportsweak =
+        do_QueryInterface(aWebBrowserChrome);
+    if (supportsweak) {
+      supportsweak->GetWeakReference(getter_AddRefs(mWebBrowserChromeWeak));
+    } else {
+      nsCOMPtr<nsIEmbeddingSiteWindow> ownerWin(
+          do_QueryInterface(aWebBrowserChrome));
+      nsCOMPtr<nsIInterfaceRequestor> requestor(
+          do_QueryInterface(aWebBrowserChrome));
+
+      // it's ok for ownerWin or requestor to be null.
+      mWebBrowserChrome = aWebBrowserChrome;
+      mOwnerWin = ownerWin;
+      mOwnerRequestor = requestor;
+    }
+  }
+
+  if (mContentTreeOwner) {
+    mContentTreeOwner->SetWebBrowserChrome(aWebBrowserChrome);
+  }
+
+  return NS_OK;
+}
+
+// Hook up things to the chrome like context menus and tooltips, if the chrome
+// has implemented the right interfaces.
+NS_IMETHODIMP
+nsDocShellTreeOwner::AddChromeListeners() {
+  nsresult rv = NS_OK;
+
+  nsCOMPtr<nsIWebBrowserChrome> webBrowserChrome = GetWebBrowserChrome();
+  if (!webBrowserChrome) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // install tooltips
+  if (!mChromeTooltipListener) {
+    nsCOMPtr<nsITooltipListener> tooltipListener(
+        do_QueryInterface(webBrowserChrome));
+    if (tooltipListener) {
+      mChromeTooltipListener =
+          new ChromeTooltipListener(mWebBrowser, webBrowserChrome);
+      rv = mChromeTooltipListener->AddChromeListeners();
+    }
+  }
+
+  nsCOMPtr<EventTarget> target;
+  GetDOMEventTarget(mWebBrowser, getter_AddRefs(target));
+
+  // register dragover and drop event listeners with the listener manager
+  MOZ_ASSERT(target, "how does this happen? (see bug 1659758)");
+  if (target) {
+    if (EventListenerManager* elmP = target->GetOrCreateListenerManager()) {
+      elmP->AddEventListenerByType(this, u"dragover"_ns,
+                                   TrustedEventsAtSystemGroupBubble());
+      elmP->AddEventListenerByType(this, u"drop"_ns,
+                                   TrustedEventsAtSystemGroupBubble());
+    }
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::RemoveChromeListeners() {
+  if (mChromeTooltipListener) {
+    mChromeTooltipListener->RemoveChromeListeners();
+    mChromeTooltipListener = nullptr;
+  }
+
+  nsCOMPtr<EventTarget> piTarget;
+  GetDOMEventTarget(mWebBrowser, getter_AddRefs(piTarget));
+  if (!piTarget) {
+    return NS_OK;
+  }
+
+  EventListenerManager* elmP = piTarget->GetOrCreateListenerManager();
+  if (elmP) {
+    elmP->RemoveEventListenerByType(this, u"dragover"_ns,
+                                    TrustedEventsAtSystemGroupBubble());
+    elmP->RemoveEventListenerByType(this, u"drop"_ns,
+                                    TrustedEventsAtSystemGroupBubble());
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShellTreeOwner::HandleEvent(Event* aEvent) {
+  DragEvent* dragEvent = aEvent ? aEvent->AsDragEvent() : nullptr;
+  if (NS_WARN_IF(!dragEvent)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (dragEvent->DefaultPrevented()) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIDroppedLinkHandler> handler =
+      do_GetService("@mozilla.org/content/dropped-link-handler;1");
+  if (!handler) {
+    return NS_OK;
+  }
+
+  nsAutoString eventType;
+  aEvent->GetType(eventType);
+  if (eventType.EqualsLiteral("dragover")) {
+    bool canDropLink = false;
+    handler->CanDropLink(dragEvent, false, &canDropLink);
+    if (canDropLink) {
+      aEvent->PreventDefault();
+    }
+  } else if (eventType.EqualsLiteral("drop")) {
+    nsIWebNavigation* webnav = static_cast<nsIWebNavigation*>(mWebBrowser);
+
+    nsTArray<RefPtr<nsIDroppedLinkItem>> links;
+    if (webnav && NS_SUCCEEDED(handler->DropLinks(dragEvent, true, links))) {
+      if (links.Length() >= 1) {
+        nsCOMPtr<nsIPrincipal> triggeringPrincipal;
+        handler->GetTriggeringPrincipal(dragEvent,
+                                        getter_AddRefs(triggeringPrincipal));
+        if (triggeringPrincipal) {
+          nsCOMPtr<nsIWebBrowserChrome> webBrowserChrome =
+              GetWebBrowserChrome();
+          if (webBrowserChrome) {
+            nsCOMPtr<nsIBrowserChild> browserChild =
+                do_QueryInterface(webBrowserChrome);
+            if (browserChild) {
+              nsresult rv = browserChild->RemoteDropLinks(links);
+              return rv;
+            }
+          }
+          nsAutoString url;
+          if (NS_SUCCEEDED(links[0]->GetUrl(url))) {
+            if (!url.IsEmpty()) {
+#ifndef ANDROID
+              MOZ_ASSERT(triggeringPrincipal,
+                         "nsDocShellTreeOwner::HandleEvent: Need a valid "
+                         "triggeringPrincipal");
+#endif
+              LoadURIOptions loadURIOptions;
+              loadURIOptions.mTriggeringPrincipal = triggeringPrincipal;
+              nsCOMPtr<nsIContentSecurityPolicy> csp;
+              handler->GetCSP(dragEvent, getter_AddRefs(csp));
+              loadURIOptions.mCsp = csp;
+              webnav->LoadURI(url, loadURIOptions);
+            }
+          }
+        }
+      }
+    } else {
+      aEvent->StopPropagation();
+      aEvent->PreventDefault();
+    }
+  }
+
+  return NS_OK;
+}
+
+already_AddRefed<nsIWebBrowserChrome>
+nsDocShellTreeOwner::GetWebBrowserChrome() {
+  nsCOMPtr<nsIWebBrowserChrome> chrome;
+  if (mWebBrowserChromeWeak) {
+    chrome = do_QueryReferent(mWebBrowserChromeWeak);
+  } else if (mWebBrowserChrome) {
+    chrome = mWebBrowserChrome;
+  }
+  return chrome.forget();
+}
+
+already_AddRefed<nsIEmbeddingSiteWindow> nsDocShellTreeOwner::GetOwnerWin() {
+  nsCOMPtr<nsIEmbeddingSiteWindow> win;
+  if (mWebBrowserChromeWeak) {
+    win = do_QueryReferent(mWebBrowserChromeWeak);
+  } else if (mOwnerWin) {
+    win = mOwnerWin;
+  }
+  return win.forget();
+}
+
+already_AddRefed<nsIInterfaceRequestor>
+nsDocShellTreeOwner::GetOwnerRequestor() {
+  nsCOMPtr<nsIInterfaceRequestor> req;
+  if (mWebBrowserChromeWeak) {
+    req = do_QueryReferent(mWebBrowserChromeWeak);
+  } else if (mOwnerRequestor) {
+    req = mOwnerRequestor;
+  }
+  return req.forget();
+}
+
+NS_IMPL_ISUPPORTS(ChromeTooltipListener, nsIDOMEventListener)
+
+ChromeTooltipListener::ChromeTooltipListener(nsWebBrowser* aInBrowser,
+                                             nsIWebBrowserChrome* aInChrome)
+    : mWebBrowser(aInBrowser),
+      mWebBrowserChrome(aInChrome),
+      mTooltipListenerInstalled(false),
+      mMouseClientX(0),
+      mMouseClientY(0),
+      mMouseScreenX(0),
+      mMouseScreenY(0),
+      mShowingTooltip(false),
+      mTooltipShownOnce(false) {}
+
+ChromeTooltipListener::~ChromeTooltipListener() {}
+
+nsITooltipTextProvider* ChromeTooltipListener::GetTooltipTextProvider() {
+  if (!mTooltipTextProvider) {
+    mTooltipTextProvider = do_GetService(NS_TOOLTIPTEXTPROVIDER_CONTRACTID);
+  }
+
+  if (!mTooltipTextProvider) {
+    mTooltipTextProvider =
+        do_GetService(NS_DEFAULTTOOLTIPTEXTPROVIDER_CONTRACTID);
+  }
+
+  return mTooltipTextProvider;
+}
+
+// Hook up things to the chrome like context menus and tooltips, if the chrome
+// has implemented the right interfaces.
+NS_IMETHODIMP
+ChromeTooltipListener::AddChromeListeners() {
+  if (!mEventTarget) {
+    GetDOMEventTarget(mWebBrowser, getter_AddRefs(mEventTarget));
+  }
+
+  // Register the appropriate events for tooltips, but only if
+  // the embedding chrome cares.
+  nsresult rv = NS_OK;
+  nsCOMPtr<nsITooltipListener> tooltipListener(
+      do_QueryInterface(mWebBrowserChrome));
+  if (tooltipListener && !mTooltipListenerInstalled) {
+    rv = AddTooltipListener();
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+  }
+
+  return rv;
+}
+
+// Subscribe to the events that will allow us to track tooltips. We need "mouse"
+// for mouseExit, "mouse motion" for mouseMove, and "key" for keyDown. As we
+// add the listeners, keep track of how many succeed so we can clean up
+// correctly in Release().
+NS_IMETHODIMP
+ChromeTooltipListener::AddTooltipListener() {
+  if (mEventTarget) {
+    nsresult rv = NS_OK;
+#ifndef XP_WIN
+    rv =
+        mEventTarget->AddSystemEventListener(u"keydown"_ns, this, false, false);
+    NS_ENSURE_SUCCESS(rv, rv);
+#endif
+    rv = mEventTarget->AddSystemEventListener(u"mousedown"_ns, this, false,
+                                              false);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mEventTarget->AddSystemEventListener(u"mouseout"_ns, this, false,
+                                              false);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mEventTarget->AddSystemEventListener(u"mousemove"_ns, this, false,
+                                              false);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    mTooltipListenerInstalled = true;
+  }
+
+  return NS_OK;
+}
+
+// Unsubscribe from the various things we've hooked up to the window root.
+NS_IMETHODIMP
+ChromeTooltipListener::RemoveChromeListeners() {
+  HideTooltip();
+
+  if (mTooltipListenerInstalled) {
+    RemoveTooltipListener();
+  }
+
+  mEventTarget = nullptr;
+
+  // it really doesn't matter if these fail...
+  return NS_OK;
+}
+
+// Unsubscribe from all the various tooltip events that we were listening to.
+NS_IMETHODIMP
+ChromeTooltipListener::RemoveTooltipListener() {
+  if (mEventTarget) {
+#ifndef XP_WIN
+    mEventTarget->RemoveSystemEventListener(u"keydown"_ns, this, false);
+#endif
+    mEventTarget->RemoveSystemEventListener(u"mousedown"_ns, this, false);
+    mEventTarget->RemoveSystemEventListener(u"mouseout"_ns, this, false);
+    mEventTarget->RemoveSystemEventListener(u"mousemove"_ns, this, false);
+    mTooltipListenerInstalled = false;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ChromeTooltipListener::HandleEvent(Event* aEvent) {
+  nsAutoString eventType;
+  aEvent->GetType(eventType);
+
+  if (eventType.EqualsLiteral("mousedown")) {
+    return HideTooltip();
+  } else if (eventType.EqualsLiteral("keydown")) {
+    WidgetKeyboardEvent* keyEvent = aEvent->WidgetEventPtr()->AsKeyboardEvent();
+    if (!keyEvent->IsModifierKeyEvent()) {
+      return HideTooltip();
+    }
+
+    return NS_OK;
+  } else if (eventType.EqualsLiteral("mouseout")) {
+    // Reset flag so that tooltip will display on the next MouseMove
+    mTooltipShownOnce = false;
+    return HideTooltip();
+  } else if (eventType.EqualsLiteral("mousemove")) {
+    return MouseMove(aEvent);
+  }
+
+  NS_ERROR("Unexpected event type");
+  return NS_OK;
+}
+
+// If we're a tooltip, fire off a timer to see if a tooltip should be shown. If
+// the timer fires, we cache the node in |mPossibleTooltipNode|.
+nsresult ChromeTooltipListener::MouseMove(Event* aMouseEvent) {
+  MouseEvent* mouseEvent = aMouseEvent->AsMouseEvent();
+  if (!mouseEvent) {
+    return NS_OK;
+  }
+
+  // stash the coordinates of the event so that we can still get back to it from
+  // within the timer callback. On win32, we'll get a MouseMove event even when
+  // a popup goes away -- even when the mouse doesn't change position! To get
+  // around this, we make sure the mouse has really moved before proceeding.
+  int32_t newMouseX = mouseEvent->ClientX();
+  int32_t newMouseY = mouseEvent->ClientY();
+  if (mMouseClientX == newMouseX && mMouseClientY == newMouseY) {
+    return NS_OK;
+  }
+
+  // Filter out minor mouse movements.
+  if (mShowingTooltip &&
+      (abs(mMouseClientX - newMouseX) <= kTooltipMouseMoveTolerance) &&
+      (abs(mMouseClientY - newMouseY) <= kTooltipMouseMoveTolerance)) {
+    return NS_OK;
+  }
+
+  mMouseClientX = newMouseX;
+  mMouseClientY = newMouseY;
+  mMouseScreenX = mouseEvent->ScreenX(CallerType::System);
+  mMouseScreenY = mouseEvent->ScreenY(CallerType::System);
+
+  if (mTooltipTimer) {
+    mTooltipTimer->Cancel();
+    mTooltipTimer = nullptr;
+  }
+
+  if (!mShowingTooltip) {
+    nsIEventTarget* target = nullptr;
+    if (nsCOMPtr<EventTarget> eventTarget = aMouseEvent->GetComposedTarget()) {
+      mPossibleTooltipNode = do_QueryInterface(eventTarget);
+      nsCOMPtr<nsIGlobalObject> global(eventTarget->GetOwnerGlobal());
+      if (global) {
+        target = global->EventTargetFor(TaskCategory::UI);
+      }
+    }
+
+    if (mPossibleTooltipNode) {
+      nsresult rv = NS_NewTimerWithFuncCallback(
+          getter_AddRefs(mTooltipTimer), sTooltipCallback, this,
+          LookAndFeel::GetInt(LookAndFeel::IntID::TooltipDelay, 500),
+          nsITimer::TYPE_ONE_SHOT, "ChromeTooltipListener::MouseMove", target);
+      if (NS_FAILED(rv)) {
+        mPossibleTooltipNode = nullptr;
+        NS_WARNING("Could not create a timer for tooltip tracking");
+      }
+    }
+  } else {
+    mTooltipShownOnce = true;
+    return HideTooltip();
+  }
+
+  return NS_OK;
+}
+
+// Tell the registered chrome that they should show the tooltip.
+NS_IMETHODIMP
+ChromeTooltipListener::ShowTooltip(int32_t aInXCoords, int32_t aInYCoords,
+                                   const nsAString& aInTipText,
+                                   const nsAString& aTipDir) {
+  nsresult rv = NS_OK;
+
+  // do the work to call the client
+  nsCOMPtr<nsITooltipListener> tooltipListener(
+      do_QueryInterface(mWebBrowserChrome));
+  if (tooltipListener) {
+    rv = tooltipListener->OnShowTooltip(aInXCoords, aInYCoords, aInTipText,
+                                        aTipDir);
+    if (NS_SUCCEEDED(rv)) {
+      mShowingTooltip = true;
+    }
+  }
+
+  return rv;
+}
+
+// Tell the registered chrome that they should rollup the tooltip
+// NOTE: This routine is safe to call even if the popup is already closed.
+NS_IMETHODIMP
+ChromeTooltipListener::HideTooltip() {
+  nsresult rv = NS_OK;
+
+  // shut down the relevant timers
+  if (mTooltipTimer) {
+    mTooltipTimer->Cancel();
+    mTooltipTimer = nullptr;
+    // release tooltip target
+    mPossibleTooltipNode = nullptr;
+    mLastDocshell = nullptr;
+  }
+
+  // if we're showing the tip, tell the chrome to hide it
+  if (mShowingTooltip) {
+    nsCOMPtr<nsITooltipListener> tooltipListener(
+        do_QueryInterface(mWebBrowserChrome));
+    if (tooltipListener) {
+      rv = tooltipListener->OnHideTooltip();
+      if (NS_SUCCEEDED(rv)) {
+        mShowingTooltip = false;
+      }
+    }
+  }
+
+  return rv;
+}
+
+bool ChromeTooltipListener::WebProgressShowedTooltip(
+    nsIWebProgress* aWebProgress) {
+  nsCOMPtr<nsIDocShell> docshell = do_QueryInterface(aWebProgress);
+  nsCOMPtr<nsIDocShell> lastUsed = do_QueryReferent(mLastDocshell);
+  while (lastUsed) {
+    if (lastUsed == docshell) {
+      return true;
+    }
+    // We can't use the docshell hierarchy here, because when the parent
+    // docshell is navigated, the child docshell is disconnected (ie its
+    // references to the parent are nulled out) despite it still being
+    // alive here. So we use the document hierarchy instead:
+    Document* document = lastUsed->GetDocument();
+    if (document) {
+      document = document->GetInProcessParentDocument();
+    }
+    if (!document) {
+      break;
+    }
+    lastUsed = document->GetDocShell();
+  }
+  return false;
+}
+
+// A timer callback, fired when the mouse has hovered inside of a frame for the
+// appropriate amount of time. Getting to this point means that we should show
+// the tooltip, but only after we determine there is an appropriate TITLE
+// element.
+//
+// This relies on certain things being cached into the |aChromeTooltipListener|
+// object passed to us by the timer:
+//   -- the x/y coordinates of the mouse      (mMouseClientY, mMouseClientX)
+//   -- the dom node the user hovered over    (mPossibleTooltipNode)
+void ChromeTooltipListener::sTooltipCallback(nsITimer* aTimer,
+                                             void* aChromeTooltipListener) {
+  auto self = static_cast<ChromeTooltipListener*>(aChromeTooltipListener);
+  if (self && self->mPossibleTooltipNode) {
+    // release tooltip target once done, no matter what we do here.
+    auto cleanup = MakeScopeExit([&] { self->mPossibleTooltipNode = nullptr; });
+    if (!self->mPossibleTooltipNode->IsInComposedDoc()) {
+      return;
+    }
+    // Check that the document or its ancestors haven't been replaced.
+    Document* doc = self->mPossibleTooltipNode->OwnerDoc();
+    while (doc) {
+      if (!doc->IsCurrentActiveDocument()) {
+        return;
+      }
+      doc = doc->GetInProcessParentDocument();
+    }
+
+    // The actual coordinates we want to put the tooltip at are relative to the
+    // toplevel docshell of our mWebBrowser.  We know what the screen
+    // coordinates of the mouse event were, which means we just need the screen
+    // coordinates of the docshell.  Unfortunately, there is no good way to
+    // find those short of groveling for the presentation in that docshell and
+    // finding the screen coords of its toplevel widget...
+    nsCOMPtr<nsIDocShell> docShell =
+        do_GetInterface(static_cast<nsIWebBrowser*>(self->mWebBrowser));
+    RefPtr<PresShell> presShell = docShell ? docShell->GetPresShell() : nullptr;
+
+    nsIWidget* widget = nullptr;
+    if (presShell) {
+      nsViewManager* vm = presShell->GetViewManager();
+      if (vm) {
+        nsView* view = vm->GetRootView();
+        if (view) {
+          nsPoint offset;
+          widget = view->GetNearestWidget(&offset);
+        }
+      }
+    }
+
+    if (!widget || !docShell || !docShell->GetBrowsingContext()->IsActive()) {
+      return;
+    }
+
+    // if there is text associated with the node, show the tip and fire
+    // off a timer to auto-hide it.
+    nsITooltipTextProvider* tooltipProvider = self->GetTooltipTextProvider();
+    if (tooltipProvider) {
+      nsString tooltipText;
+      nsString directionText;
+      bool textFound = false;
+      tooltipProvider->GetNodeText(self->mPossibleTooltipNode,
+                                   getter_Copies(tooltipText),
+                                   getter_Copies(directionText), &textFound);
+
+      if (textFound && (!self->mTooltipShownOnce ||
+                        tooltipText != self->mLastShownTooltipText)) {
+        // ShowTooltip expects screen-relative position.
+        self->ShowTooltip(self->mMouseScreenX, self->mMouseScreenY, tooltipText,
+                          directionText);
+        self->mLastShownTooltipText = std::move(tooltipText);
+        self->mLastDocshell = do_GetWeakReference(
+            self->mPossibleTooltipNode->OwnerDoc()->GetDocShell());
+      }
+    }
+  }
+}