Adding upstream version 110.0.1.upstream/110.0.1upstream

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

1 files changed, 1845 insertions, 0 deletions

diff --git a/browser/components/shell/nsWindowsShellService.cpp b/browser/components/shell/nsWindowsShellService.cpp
new file mode 100644
index 0000000000..6863ad300c
--- /dev/null
+++ b/browser/components/shell/nsWindowsShellService.cpp
@@ -0,0 +1,1845 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#define UNICODE
+
+#include "nsWindowsShellService.h"
+
+#include "BinaryPath.h"
+#include "imgIContainer.h"
+#include "imgIRequest.h"
+#include "mozilla/RefPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIContent.h"
+#include "nsIImageLoadingContent.h"
+#include "nsIOutputStream.h"
+#include "nsIPrefService.h"
+#include "nsIStringBundle.h"
+#include "nsNetUtil.h"
+#include "nsServiceManagerUtils.h"
+#include "nsShellService.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsIWindowsRegKey.h"
+#include "nsUnicharUtils.h"
+#include "nsIURLFormatter.h"
+#include "nsXULAppAPI.h"
+#include "mozilla/WindowsVersion.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/intl/Localization.h"
+#include "WindowsDefaultBrowser.h"
+#include "WindowsUserChoice.h"
+#include "nsLocalFile.h"
+#include "nsIXULAppInfo.h"
+#include "nsINIParser.h"
+#include "nsNativeAppSupportWin.h"
+#include "nsWindowsHelpers.h"
+
+#include <windows.h>
+#include <shellapi.h>
+#include <propvarutil.h>
+#include <propkey.h>
+
+#ifdef __MINGW32__
+// MinGW-w64 headers are missing PropVariantToString.
+#  include <propsys.h>
+PSSTDAPI PropVariantToString(REFPROPVARIANT propvar, PWSTR psz, UINT cch);
+#  define UNLEN 256
+#else
+#  include <Lmcons.h>  // For UNLEN
+#endif
+
+#include <comutil.h>
+#include <objbase.h>
+#include <shlobj.h>
+#include <knownfolders.h>
+#include "WinUtils.h"
+#include "mozilla/widget/WinTaskbar.h"
+
+#include <mbstring.h>
+
+#define PIN_TO_TASKBAR_SHELL_VERB 5386
+#define PRIVATE_BROWSING_BINARY L"private_browsing.exe"
+
+#undef ACCESS_READ
+
+#ifndef MAX_BUF
+#  define MAX_BUF 4096
+#endif
+
+#define REG_SUCCEEDED(val) (val == ERROR_SUCCESS)
+
+#define REG_FAILED(val) (val != ERROR_SUCCESS)
+
+#ifdef DEBUG
+#  define NS_ENSURE_HRESULT(hres, ret)                    \
+    do {                                                  \
+      HRESULT result = hres;                              \
+      if (MOZ_UNLIKELY(FAILED(result))) {                 \
+        mozilla::SmprintfPointer msg = mozilla::Smprintf( \
+            "NS_ENSURE_HRESULT(%s, %s) failed with "      \
+            "result 0x%" PRIX32,                          \
+            #hres, #ret, static_cast<uint32_t>(result));  \
+        NS_WARNING(msg.get());                            \
+        return ret;                                       \
+      }                                                   \
+    } while (false)
+#else
+#  define NS_ENSURE_HRESULT(hres, ret) \
+    if (MOZ_UNLIKELY(FAILED(hres))) return ret
+#endif
+
+using mozilla::IsWin8OrLater;
+using namespace mozilla;
+using mozilla::intl::Localization;
+
+struct SysFreeStringDeleter {
+  void operator()(BSTR aPtr) { ::SysFreeString(aPtr); }
+};
+using BStrPtr = mozilla::UniquePtr<OLECHAR, SysFreeStringDeleter>;
+
+NS_IMPL_ISUPPORTS(nsWindowsShellService, nsIToolkitShellService,
+                  nsIShellService, nsIWindowsShellService)
+
+static nsresult OpenKeyForReading(HKEY aKeyRoot, const nsAString& aKeyName,
+                                  HKEY* aKey) {
+  const nsString& flatName = PromiseFlatString(aKeyName);
+
+  DWORD res = ::RegOpenKeyExW(aKeyRoot, flatName.get(), 0, KEY_READ, aKey);
+  switch (res) {
+    case ERROR_SUCCESS:
+      break;
+    case ERROR_ACCESS_DENIED:
+      return NS_ERROR_FILE_ACCESS_DENIED;
+    case ERROR_FILE_NOT_FOUND:
+      return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  return NS_OK;
+}
+
+nsresult GetHelperPath(nsAutoString& aPath) {
+  nsresult rv;
+  nsCOMPtr<nsIProperties> directoryService =
+      do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> appHelper;
+  rv = directoryService->Get(XRE_EXECUTABLE_FILE, NS_GET_IID(nsIFile),
+                             getter_AddRefs(appHelper));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = appHelper->SetNativeLeafName("uninstall"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = appHelper->AppendNative("helper.exe"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = appHelper->GetPath(aPath);
+
+  aPath.Insert(L'"', 0);
+  aPath.Append(L'"');
+  return rv;
+}
+
+nsresult LaunchHelper(nsAutoString& aPath) {
+  STARTUPINFOW si = {sizeof(si), 0};
+  PROCESS_INFORMATION pi = {0};
+
+  if (!CreateProcessW(nullptr, (LPWSTR)aPath.get(), nullptr, nullptr, FALSE, 0,
+                      nullptr, nullptr, &si, &pi)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  CloseHandle(pi.hProcess);
+  CloseHandle(pi.hThread);
+  return NS_OK;
+}
+
+static bool IsPathDefaultForClass(
+    const RefPtr<IApplicationAssociationRegistration>& pAAR, wchar_t* exePath,
+    LPCWSTR aClassName) {
+  LPWSTR registeredApp;
+  bool isProtocol = *aClassName != L'.';
+  ASSOCIATIONTYPE queryType = isProtocol ? AT_URLPROTOCOL : AT_FILEEXTENSION;
+  HRESULT hr = pAAR->QueryCurrentDefault(aClassName, queryType, AL_EFFECTIVE,
+                                         &registeredApp);
+  if (FAILED(hr)) {
+    return false;
+  }
+
+  nsAutoString regAppName(registeredApp);
+  CoTaskMemFree(registeredApp);
+
+  // Make sure the application path for this progID is this installation.
+  regAppName.AppendLiteral("\\shell\\open\\command");
+  HKEY theKey;
+  nsresult rv = OpenKeyForReading(HKEY_CLASSES_ROOT, regAppName, &theKey);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  wchar_t cmdFromReg[MAX_BUF] = L"";
+  DWORD len = sizeof(cmdFromReg);
+  DWORD res = ::RegQueryValueExW(theKey, nullptr, nullptr, nullptr,
+                                 (LPBYTE)cmdFromReg, &len);
+  ::RegCloseKey(theKey);
+  if (REG_FAILED(res)) {
+    return false;
+  }
+
+  nsAutoString pathFromReg(cmdFromReg);
+  nsLocalFile::CleanupCmdHandlerPath(pathFromReg);
+
+  return _wcsicmp(exePath, pathFromReg.Data()) == 0;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::IsDefaultBrowser(bool aForAllTypes,
+                                        bool* aIsDefaultBrowser) {
+  *aIsDefaultBrowser = false;
+
+  RefPtr<IApplicationAssociationRegistration> pAAR;
+  HRESULT hr = CoCreateInstance(
+      CLSID_ApplicationAssociationRegistration, nullptr, CLSCTX_INPROC,
+      IID_IApplicationAssociationRegistration, getter_AddRefs(pAAR));
+  if (FAILED(hr)) {
+    return NS_OK;
+  }
+
+  wchar_t exePath[MAXPATHLEN] = L"";
+  nsresult rv = BinaryPath::GetLong(exePath);
+
+  if (NS_FAILED(rv)) {
+    return NS_OK;
+  }
+
+  *aIsDefaultBrowser = IsPathDefaultForClass(pAAR, exePath, L"http");
+  if (*aIsDefaultBrowser && aForAllTypes) {
+    *aIsDefaultBrowser = IsPathDefaultForClass(pAAR, exePath, L".html");
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::IsDefaultHandlerFor(
+    const nsAString& aFileExtensionOrProtocol, bool* aIsDefaultHandlerFor) {
+  *aIsDefaultHandlerFor = false;
+
+  RefPtr<IApplicationAssociationRegistration> pAAR;
+  HRESULT hr = CoCreateInstance(
+      CLSID_ApplicationAssociationRegistration, nullptr, CLSCTX_INPROC,
+      IID_IApplicationAssociationRegistration, getter_AddRefs(pAAR));
+  if (FAILED(hr)) {
+    return NS_OK;
+  }
+
+  wchar_t exePath[MAXPATHLEN] = L"";
+  nsresult rv = BinaryPath::GetLong(exePath);
+
+  if (NS_FAILED(rv)) {
+    return NS_OK;
+  }
+
+  const nsString& flatClass = PromiseFlatString(aFileExtensionOrProtocol);
+
+  *aIsDefaultHandlerFor = IsPathDefaultForClass(pAAR, exePath, flatClass.get());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::QueryCurrentDefaultHandlerFor(
+    const nsAString& aFileExtensionOrProtocol, nsAString& aResult) {
+  aResult.Truncate();
+
+  RefPtr<IApplicationAssociationRegistration> pAAR;
+  HRESULT hr = CoCreateInstance(
+      CLSID_ApplicationAssociationRegistration, nullptr, CLSCTX_INPROC,
+      IID_IApplicationAssociationRegistration, getter_AddRefs(pAAR));
+  if (FAILED(hr)) {
+    return NS_OK;
+  }
+
+  const nsString& flatClass = PromiseFlatString(aFileExtensionOrProtocol);
+
+  LPWSTR registeredApp;
+  bool isProtocol = flatClass.First() != L'.';
+  ASSOCIATIONTYPE queryType = isProtocol ? AT_URLPROTOCOL : AT_FILEEXTENSION;
+  hr = pAAR->QueryCurrentDefault(flatClass.get(), queryType, AL_EFFECTIVE,
+                                 &registeredApp);
+  if (hr == HRESULT_FROM_WIN32(ERROR_NO_ASSOCIATION)) {
+    return NS_OK;
+  }
+  NS_ENSURE_HRESULT(hr, NS_ERROR_FAILURE);
+
+  aResult = registeredApp;
+  CoTaskMemFree(registeredApp);
+
+  return NS_OK;
+}
+
+nsresult nsWindowsShellService::LaunchControlPanelDefaultsSelectionUI() {
+  IApplicationAssociationRegistrationUI* pAARUI;
+  HRESULT hr = CoCreateInstance(
+      CLSID_ApplicationAssociationRegistrationUI, NULL, CLSCTX_INPROC,
+      IID_IApplicationAssociationRegistrationUI, (void**)&pAARUI);
+  if (SUCCEEDED(hr)) {
+    mozilla::UniquePtr<wchar_t[]> appRegName;
+    GetAppRegName(appRegName);
+    hr = pAARUI->LaunchAdvancedAssociationUI(appRegName.get());
+    pAARUI->Release();
+  }
+  return SUCCEEDED(hr) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult nsWindowsShellService::LaunchControlPanelDefaultPrograms() {
+  return ::LaunchControlPanelDefaultPrograms() ? NS_OK : NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::CheckAllProgIDsExist(bool* aResult) {
+  *aResult = false;
+  nsAutoString aumid;
+  if (!mozilla::widget::WinTaskbar::GetAppUserModelID(aumid)) {
+    return NS_OK;
+  }
+  *aResult =
+      CheckProgIDExists(FormatProgID(L"FirefoxURL", aumid.get()).get()) &&
+      CheckProgIDExists(FormatProgID(L"FirefoxHTML", aumid.get()).get()) &&
+      CheckProgIDExists(FormatProgID(L"FirefoxPDF", aumid.get()).get());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::CheckBrowserUserChoiceHashes(bool* aResult) {
+  *aResult = ::CheckBrowserUserChoiceHashes();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::CanSetDefaultBrowserUserChoice(bool* aResult) {
+  *aResult = false;
+// If the WDBA is not available, this could never succeed.
+#ifdef MOZ_DEFAULT_BROWSER_AGENT
+  bool progIDsExist = false;
+  bool hashOk = false;
+  *aResult = NS_SUCCEEDED(CheckAllProgIDsExist(&progIDsExist)) &&
+             progIDsExist &&
+             NS_SUCCEEDED(CheckBrowserUserChoiceHashes(&hashOk)) && hashOk;
+#endif
+  return NS_OK;
+}
+
+nsresult nsWindowsShellService::LaunchModernSettingsDialogDefaultApps() {
+  return ::LaunchModernSettingsDialogDefaultApps() ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult nsWindowsShellService::InvokeHTTPOpenAsVerb() {
+  nsCOMPtr<nsIURLFormatter> formatter(
+      do_GetService("@mozilla.org/toolkit/URLFormatterService;1"));
+  if (!formatter) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsString urlStr;
+  nsresult rv = formatter->FormatURLPref(u"app.support.baseURL"_ns, urlStr);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  if (!StringBeginsWith(urlStr, u"https://"_ns)) {
+    return NS_ERROR_FAILURE;
+  }
+  urlStr.AppendLiteral("win10-default-browser");
+
+  SHELLEXECUTEINFOW seinfo = {sizeof(SHELLEXECUTEINFOW)};
+  seinfo.lpVerb = L"openas";
+  seinfo.lpFile = urlStr.get();
+  seinfo.nShow = SW_SHOWNORMAL;
+  if (!ShellExecuteExW(&seinfo)) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+nsresult nsWindowsShellService::LaunchHTTPHandlerPane() {
+  OPENASINFO info;
+  info.pcszFile = L"http";
+  info.pcszClass = nullptr;
+  info.oaifInFlags =
+      OAIF_FORCE_REGISTRATION | OAIF_URL_PROTOCOL | OAIF_REGISTER_EXT;
+
+  HRESULT hr = SHOpenWithDialog(nullptr, &info);
+  if (SUCCEEDED(hr) || (hr == HRESULT_FROM_WIN32(ERROR_CANCELLED))) {
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::SetDefaultBrowser(bool aClaimAllTypes,
+                                         bool aForAllUsers) {
+  // If running from within a package, don't attempt to set default with
+  // the helper, as it will not work and will only confuse our package's
+  // virtualized registry.
+  nsresult rv = NS_OK;
+  if (!widget::WinUtils::HasPackageIdentity()) {
+    nsAutoString appHelperPath;
+    if (NS_FAILED(GetHelperPath(appHelperPath))) return NS_ERROR_FAILURE;
+
+    if (aForAllUsers) {
+      appHelperPath.AppendLiteral(" /SetAsDefaultAppGlobal");
+    } else {
+      appHelperPath.AppendLiteral(" /SetAsDefaultAppUser");
+    }
+
+    rv = LaunchHelper(appHelperPath);
+  }
+
+  if (NS_SUCCEEDED(rv) && IsWin8OrLater()) {
+    if (aClaimAllTypes) {
+      if (IsWin10OrLater()) {
+        rv = LaunchModernSettingsDialogDefaultApps();
+      } else {
+        rv = LaunchControlPanelDefaultsSelectionUI();
+      }
+      // The above call should never really fail, but just in case
+      // fall back to showing the HTTP association screen only.
+      if (NS_FAILED(rv)) {
+        if (IsWin10OrLater()) {
+          rv = InvokeHTTPOpenAsVerb();
+        } else {
+          rv = LaunchHTTPHandlerPane();
+        }
+      }
+    } else {
+      // Windows 10 blocks attempts to load the
+      // HTTP Handler association dialog.
+      if (IsWin10OrLater()) {
+        rv = LaunchModernSettingsDialogDefaultApps();
+      } else {
+        rv = LaunchHTTPHandlerPane();
+      }
+
+      // The above call should never really fail, but just in case
+      // fall back to showing control panel for all defaults
+      if (NS_FAILED(rv)) {
+        rv = LaunchControlPanelDefaultsSelectionUI();
+      }
+    }
+  }
+
+  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
+  if (prefs) {
+    (void)prefs->SetBoolPref(PREF_CHECKDEFAULTBROWSER, true);
+    // Reset the number of times the dialog should be shown
+    // before it is silenced.
+    (void)prefs->SetIntPref(PREF_DEFAULTBROWSERCHECKCOUNT, 0);
+  }
+
+  return rv;
+}
+
+static nsresult WriteBitmap(nsIFile* aFile, imgIContainer* aImage) {
+  nsresult rv;
+
+  RefPtr<gfx::SourceSurface> surface = aImage->GetFrame(
+      imgIContainer::FRAME_FIRST, imgIContainer::FLAG_SYNC_DECODE);
+  NS_ENSURE_TRUE(surface, NS_ERROR_FAILURE);
+
+  // For either of the following formats we want to set the biBitCount member
+  // of the BITMAPINFOHEADER struct to 32, below. For that value the bitmap
+  // format defines that the A8/X8 WORDs in the bitmap byte stream be ignored
+  // for the BI_RGB value we use for the biCompression member.
+  MOZ_ASSERT(surface->GetFormat() == gfx::SurfaceFormat::B8G8R8A8 ||
+             surface->GetFormat() == gfx::SurfaceFormat::B8G8R8X8);
+
+  RefPtr<gfx::DataSourceSurface> dataSurface = surface->GetDataSurface();
+  NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+
+  int32_t width = dataSurface->GetSize().width;
+  int32_t height = dataSurface->GetSize().height;
+  int32_t bytesPerPixel = 4 * sizeof(uint8_t);
+  uint32_t bytesPerRow = bytesPerPixel * width;
+
+  // initialize these bitmap structs which we will later
+  // serialize directly to the head of the bitmap file
+  BITMAPINFOHEADER bmi;
+  bmi.biSize = sizeof(BITMAPINFOHEADER);
+  bmi.biWidth = width;
+  bmi.biHeight = height;
+  bmi.biPlanes = 1;
+  bmi.biBitCount = (WORD)bytesPerPixel * 8;
+  bmi.biCompression = BI_RGB;
+  bmi.biSizeImage = bytesPerRow * height;
+  bmi.biXPelsPerMeter = 0;
+  bmi.biYPelsPerMeter = 0;
+  bmi.biClrUsed = 0;
+  bmi.biClrImportant = 0;
+
+  BITMAPFILEHEADER bf;
+  bf.bfType = 0x4D42;  // 'BM'
+  bf.bfReserved1 = 0;
+  bf.bfReserved2 = 0;
+  bf.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
+  bf.bfSize = bf.bfOffBits + bmi.biSizeImage;
+
+  // get a file output stream
+  nsCOMPtr<nsIOutputStream> stream;
+  rv = NS_NewLocalFileOutputStream(getter_AddRefs(stream), aFile);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  gfx::DataSourceSurface::MappedSurface map;
+  if (!dataSurface->Map(gfx::DataSourceSurface::MapType::READ, &map)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // write the bitmap headers and rgb pixel data to the file
+  rv = NS_ERROR_FAILURE;
+  if (stream) {
+    uint32_t written;
+    stream->Write((const char*)&bf, sizeof(BITMAPFILEHEADER), &written);
+    if (written == sizeof(BITMAPFILEHEADER)) {
+      stream->Write((const char*)&bmi, sizeof(BITMAPINFOHEADER), &written);
+      if (written == sizeof(BITMAPINFOHEADER)) {
+        // write out the image data backwards because the desktop won't
+        // show bitmaps with negative heights for top-to-bottom
+        uint32_t i = map.mStride * height;
+        do {
+          i -= map.mStride;
+          stream->Write(((const char*)map.mData) + i, bytesPerRow, &written);
+          if (written == bytesPerRow) {
+            rv = NS_OK;
+          } else {
+            rv = NS_ERROR_FAILURE;
+            break;
+          }
+        } while (i != 0);
+      }
+    }
+
+    stream->Close();
+  }
+
+  dataSurface->Unmap();
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::SetDesktopBackground(dom::Element* aElement,
+                                            int32_t aPosition,
+                                            const nsACString& aImageName) {
+  if (!aElement || !aElement->IsHTMLElement(nsGkAtoms::img)) {
+    // XXX write background loading stuff!
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsresult rv;
+  nsCOMPtr<nsIImageLoadingContent> imageContent =
+      do_QueryInterface(aElement, &rv);
+  if (!imageContent) return rv;
+
+  // get the image container
+  nsCOMPtr<imgIRequest> request;
+  rv = imageContent->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST,
+                                getter_AddRefs(request));
+  if (!request) return rv;
+
+  nsCOMPtr<imgIContainer> container;
+  rv = request->GetImage(getter_AddRefs(container));
+  if (!container) return NS_ERROR_FAILURE;
+
+  // get the file name from localized strings
+  nsCOMPtr<nsIStringBundleService> bundleService(
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID, &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIStringBundle> shellBundle;
+  rv = bundleService->CreateBundle(SHELLSERVICE_PROPERTIES,
+                                   getter_AddRefs(shellBundle));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // e.g. "Desktop Background.bmp"
+  nsAutoString fileLeafName;
+  rv = shellBundle->GetStringFromName("desktopBackgroundLeafNameWin",
+                                      fileLeafName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // get the profile root directory
+  nsCOMPtr<nsIFile> file;
+  rv = NS_GetSpecialDirectory(NS_APP_APPLICATION_REGISTRY_DIR,
+                              getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // eventually, the path is "%APPDATA%\Mozilla\Firefox\Desktop Background.bmp"
+  rv = file->Append(fileLeafName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoString path;
+  rv = file->GetPath(path);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // write the bitmap to a file in the profile directory.
+  // We have to write old bitmap format for Windows 7 wallpapar support.
+  rv = WriteBitmap(file, container);
+
+  // if the file was written successfully, set it as the system wallpaper
+  if (NS_SUCCEEDED(rv)) {
+    nsCOMPtr<nsIWindowsRegKey> regKey =
+        do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = regKey->Create(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
+                        u"Control Panel\\Desktop"_ns,
+                        nsIWindowsRegKey::ACCESS_SET_VALUE);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsAutoString tile;
+    nsAutoString style;
+    switch (aPosition) {
+      case BACKGROUND_TILE:
+        style.Assign('0');
+        tile.Assign('1');
+        break;
+      case BACKGROUND_CENTER:
+        style.Assign('0');
+        tile.Assign('0');
+        break;
+      case BACKGROUND_STRETCH:
+        style.Assign('2');
+        tile.Assign('0');
+        break;
+      case BACKGROUND_FILL:
+        style.AssignLiteral("10");
+        tile.Assign('0');
+        break;
+      case BACKGROUND_FIT:
+        style.Assign('6');
+        tile.Assign('0');
+        break;
+      case BACKGROUND_SPAN:
+        style.AssignLiteral("22");
+        tile.Assign('0');
+        break;
+    }
+
+    rv = regKey->WriteStringValue(u"TileWallpaper"_ns, tile);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = regKey->WriteStringValue(u"WallpaperStyle"_ns, style);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = regKey->Close();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    ::SystemParametersInfoW(SPI_SETDESKWALLPAPER, 0, (PVOID)path.get(),
+                            SPIF_UPDATEINIFILE | SPIF_SENDCHANGE);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::GetDesktopBackgroundColor(uint32_t* aColor) {
+  uint32_t color = ::GetSysColor(COLOR_DESKTOP);
+  *aColor =
+      (GetRValue(color) << 16) | (GetGValue(color) << 8) | GetBValue(color);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::SetDesktopBackgroundColor(uint32_t aColor) {
+  int aParameters[2] = {COLOR_BACKGROUND, COLOR_DESKTOP};
+  BYTE r = (aColor >> 16);
+  BYTE g = (aColor << 16) >> 24;
+  BYTE b = (aColor << 24) >> 24;
+  COLORREF colors[2] = {RGB(r, g, b), RGB(r, g, b)};
+
+  ::SetSysColors(sizeof(aParameters) / sizeof(int), aParameters, colors);
+
+  nsresult rv;
+  nsCOMPtr<nsIWindowsRegKey> regKey =
+      do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = regKey->Create(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
+                      u"Control Panel\\Colors"_ns,
+                      nsIWindowsRegKey::ACCESS_SET_VALUE);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  wchar_t rgb[12];
+  _snwprintf(rgb, 12, L"%u %u %u", r, g, b);
+
+  rv = regKey->WriteStringValue(u"Background"_ns, nsDependentString(rgb));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return regKey->Close();
+}
+
+/*
+ * Writes information about a shortcut to a shortcuts log in
+ * %PROGRAMDATA%\Mozilla-1de4eec8-1241-4177-a864-e594e8d1fb38.
+ * (This is the same directory used for update staging.)
+ * For more on the shortcuts log format and purpose, consult
+ * /toolkit/mozapps/installer/windows/nsis/common.nsh.
+ *
+ * The shortcuts log created or appended here is named after
+ * the currently running application and current user SID.
+ * For example: Firefox_$SID_shortcuts.ini.
+ *
+ * If it does not exist, it will be created. If it exists
+ * and a matching shortcut named already exists in the file,
+ * a new one will not be appended.
+ *
+ * In an ideal world this function would not need aShortcutsLogDir
+ * passed to it, but it is called by at least one function that runs
+ * asynchronously, and is therefore unable to use nsDirectoryService
+ * to look it up itself.
+ */
+static nsresult WriteShortcutToLog(nsIFile* aShortcutsLogDir,
+                                   KNOWNFOLDERID aFolderId,
+                                   const nsAString& aShortcutName) {
+  // the section inside the shortcuts log
+  nsAutoCString section;
+  // the shortcuts log wants "Programs" shortcuts in its "STARTMENU" section
+  if (aFolderId == FOLDERID_CommonPrograms || aFolderId == FOLDERID_Programs) {
+    section.Assign("STARTMENU");
+  } else if (aFolderId == FOLDERID_PublicDesktop ||
+             aFolderId == FOLDERID_Desktop) {
+    section.Assign("DESKTOP");
+  } else {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsCOMPtr<nsIFile> shortcutsLog;
+  nsresult rv = aShortcutsLogDir->GetParent(getter_AddRefs(shortcutsLog));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString appName;
+  nsCOMPtr<nsIXULAppInfo> appInfo =
+      do_GetService("@mozilla.org/xre/app-info;1");
+  rv = appInfo->GetName(appName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  auto userSid = GetCurrentUserStringSid();
+  if (!userSid) {
+    return NS_ERROR_FILE_NOT_FOUND;
+  }
+
+  nsAutoString filename;
+  filename.AppendPrintf("%s_%ls_shortcuts.ini", appName.get(), userSid.get());
+  rv = shortcutsLog->Append(filename);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsINIParser parser;
+  bool fileExists = false;
+  bool shortcutsLogEntryExists = false;
+  nsAutoCString keyName, shortcutName;
+  shortcutName = NS_ConvertUTF16toUTF8(aShortcutName);
+
+  shortcutsLog->IsFile(&fileExists);
+  // if the shortcuts log exists, find either an existing matching
+  // entry, or the next available shortcut index
+  if (fileExists) {
+    rv = parser.Init(shortcutsLog);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsCString iniShortcut;
+    // surely we'll never need more than 10 shortcuts in one section...
+    for (int i = 0; i < 10; i++) {
+      keyName.AssignLiteral("Shortcut");
+      keyName.AppendInt(i);
+      rv = parser.GetString(section.get(), keyName.get(), iniShortcut);
+      if (NS_FAILED(rv)) {
+        // we found an unused index
+        break;
+      } else if (iniShortcut.Equals(shortcutName)) {
+        shortcutsLogEntryExists = true;
+      }
+    }
+    // otherwise, this is safe to use
+  } else {
+    keyName.AssignLiteral("Shortcut0");
+  }
+
+  if (!shortcutsLogEntryExists) {
+    parser.SetString(section.get(), keyName.get(), shortcutName.get());
+    // We write this ourselves instead of using parser->WriteToFile because
+    // the INI parser in our uninstaller needs to read this, and only supports
+    // UTF-16LE encoding. nsINIParser does not support UTF-16.
+    nsAutoCString formatted;
+    parser.WriteToString(formatted);
+    FILE* writeFile;
+    rv = shortcutsLog->OpenANSIFileDesc("w,ccs=UTF-16LE", &writeFile);
+    NS_ENSURE_SUCCESS(rv, rv);
+    NS_ConvertUTF8toUTF16 formattedUTF16(formatted);
+    if (fwrite(formattedUTF16.get(), sizeof(wchar_t), formattedUTF16.Length(),
+               writeFile) != formattedUTF16.Length()) {
+      fclose(writeFile);
+      return NS_ERROR_FAILURE;
+    }
+    fclose(writeFile);
+  }
+
+  return NS_OK;
+}
+
+static nsresult CreateShortcutImpl(
+    nsIFile* aBinary, const CopyableTArray<nsString>& aArguments,
+    const nsAString& aDescription, nsIFile* aIconFile, uint16_t aIconIndex,
+    const nsAString& aAppUserModelId, KNOWNFOLDERID aShortcutFolder,
+    const nsAString& aShortcutName, const nsString& aShortcutFile,
+    nsIFile* aShortcutsLogDir) {
+  NS_ENSURE_ARG(aBinary);
+  NS_ENSURE_ARG(aIconFile);
+
+  nsresult rv =
+      WriteShortcutToLog(aShortcutsLogDir, aShortcutFolder, aShortcutName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  RefPtr<IShellLinkW> link;
+  HRESULT hr = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                                IID_IShellLinkW, getter_AddRefs(link));
+  NS_ENSURE_HRESULT(hr, NS_ERROR_FAILURE);
+
+  nsString path(aBinary->NativePath());
+  link->SetPath(path.get());
+
+  wchar_t workingDir[MAX_PATH + 1];
+  wcscpy_s(workingDir, MAX_PATH + 1, aBinary->NativePath().get());
+  PathRemoveFileSpecW(workingDir);
+  link->SetWorkingDirectory(workingDir);
+
+  if (!aDescription.IsEmpty()) {
+    link->SetDescription(PromiseFlatString(aDescription).get());
+  }
+
+  // TODO: Properly escape quotes in the string, see bug 1604287.
+  nsString arguments;
+  for (auto& arg : aArguments) {
+    arguments.AppendPrintf("\"%S\" ", static_cast<const wchar_t*>(arg.get()));
+  }
+
+  link->SetArguments(arguments.get());
+
+  if (aIconFile) {
+    nsString icon(aIconFile->NativePath());
+    link->SetIconLocation(icon.get(), aIconIndex);
+  }
+
+  if (!aAppUserModelId.IsEmpty()) {
+    RefPtr<IPropertyStore> propStore;
+    hr = link->QueryInterface(IID_IPropertyStore, getter_AddRefs(propStore));
+    NS_ENSURE_HRESULT(hr, NS_ERROR_FAILURE);
+
+    PROPVARIANT pv;
+    if (FAILED(InitPropVariantFromString(
+            PromiseFlatString(aAppUserModelId).get(), &pv))) {
+      return NS_ERROR_FAILURE;
+    }
+
+    hr = propStore->SetValue(PKEY_AppUserModel_ID, pv);
+    PropVariantClear(&pv);
+    NS_ENSURE_HRESULT(hr, NS_ERROR_FAILURE);
+
+    hr = propStore->Commit();
+    NS_ENSURE_HRESULT(hr, NS_ERROR_FAILURE);
+  }
+
+  RefPtr<IPersistFile> persist;
+  hr = link->QueryInterface(IID_IPersistFile, getter_AddRefs(persist));
+  NS_ENSURE_HRESULT(hr, NS_ERROR_FAILURE);
+
+  hr = persist->Save(aShortcutFile.get(), TRUE);
+  NS_ENSURE_HRESULT(hr, NS_ERROR_FAILURE);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::CreateShortcut(
+    nsIFile* aBinary, const nsTArray<nsString>& aArguments,
+    const nsAString& aDescription, nsIFile* aIconFile, uint16_t aIconIndex,
+    const nsAString& aAppUserModelId, const nsAString& aShortcutFolder,
+    const nsAString& aShortcutName, JSContext* aCx, dom::Promise** aPromise) {
+  if (!NS_IsMainThread()) {
+    return NS_ERROR_NOT_SAME_THREAD;
+  }
+
+  ErrorResult rv;
+  RefPtr<dom::Promise> promise =
+      dom::Promise::Create(xpc::CurrentNativeGlobal(aCx), rv);
+
+  if (MOZ_UNLIKELY(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+  // In an ideal world we'd probably send along nsIFile pointers
+  // here, but it's easier to determine the needed shortcuts log
+  // entry with a KNOWNFOLDERID - so we pass this along instead
+  // and let CreateShortcutImpl take care of converting it to
+  // an nsIFile.
+  KNOWNFOLDERID folderId;
+  if (aShortcutFolder.Equals(L"Programs")) {
+    folderId = FOLDERID_Programs;
+  } else if (aShortcutFolder.Equals(L"Desktop")) {
+    folderId = FOLDERID_Desktop;
+  } else {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsCOMPtr<nsIFile> updRoot, shortcutsLogDir;
+  nsresult nsrv =
+      NS_GetSpecialDirectory(XRE_UPDATE_ROOT_DIR, getter_AddRefs(updRoot));
+  NS_ENSURE_SUCCESS(nsrv, nsrv);
+  nsrv = updRoot->GetParent(getter_AddRefs(shortcutsLogDir));
+  NS_ENSURE_SUCCESS(nsrv, nsrv);
+
+  nsCOMPtr<nsIFile> shortcutFile;
+  if (folderId == FOLDERID_Programs) {
+    nsrv = NS_GetSpecialDirectory(NS_WIN_PROGRAMS_DIR,
+                                  getter_AddRefs(shortcutFile));
+  } else if (folderId == FOLDERID_Desktop) {
+    nsrv =
+        NS_GetSpecialDirectory(NS_OS_DESKTOP_DIR, getter_AddRefs(shortcutFile));
+  } else {
+    return NS_ERROR_FILE_NOT_FOUND;
+  }
+  if (NS_FAILED(nsrv)) {
+    return NS_ERROR_FILE_NOT_FOUND;
+  }
+  shortcutFile->Append(aShortcutName);
+
+  auto promiseHolder = MakeRefPtr<nsMainThreadPtrHolder<dom::Promise>>(
+      "CreateShortcut promise", promise);
+
+  nsCOMPtr<nsIFile> binary(aBinary);
+  nsCOMPtr<nsIFile> iconFile(aIconFile);
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction(
+          "CreateShortcut",
+          [binary, aArguments = CopyableTArray<nsString>(aArguments),
+           aDescription = nsString{aDescription}, iconFile, aIconIndex,
+           aAppUserModelId = nsString{aAppUserModelId}, folderId,
+           aShortcutFolder = nsString{aShortcutFolder},
+           aShortcutName = nsString{aShortcutName}, shortcutsLogDir,
+           shortcutFile, promiseHolder = std::move(promiseHolder)] {
+            nsresult rv = NS_ERROR_FAILURE;
+            HRESULT hr = CoInitialize(nullptr);
+
+            if (SUCCEEDED(hr)) {
+              rv = CreateShortcutImpl(
+                  binary.get(), aArguments, aDescription, iconFile.get(),
+                  aIconIndex, aAppUserModelId, folderId, aShortcutName,
+                  shortcutFile->NativePath(), shortcutsLogDir.get());
+              CoUninitialize();
+            }
+
+            NS_DispatchToMainThread(NS_NewRunnableFunction(
+                "CreateShortcut callback",
+                [rv, shortcutFile, promiseHolder = std::move(promiseHolder)] {
+                  dom::Promise* promise = promiseHolder.get()->get();
+
+                  if (NS_SUCCEEDED(rv)) {
+                    promise->MaybeResolve(shortcutFile->NativePath());
+                  } else {
+                    promise->MaybeReject(rv);
+                  }
+                }));
+          }),
+      NS_DISPATCH_EVENT_MAY_BLOCK);
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+// Look for any installer-created shortcuts in the given location that match
+// the given AUMID and EXE Path. If one is found, output its path.
+//
+// NOTE: DO NOT USE if a false negative (mismatch) is unacceptable.
+// aExePath is compared directly to the path retrieved from the shortcut.
+// Due to the presence of symlinks or other filesystem issues, it's possible
+// for different paths to refer to the same file, which would cause the check
+// to fail.
+// This should rarely be an issue as we are most likely to be run from a path
+// written by the installer (shortcut, association, launch from installer),
+// which also wrote the shortcuts. But it is possible.
+//
+// aCSIDL   the CSIDL of the directory to look for matching shortcuts in
+// aAUMID   the AUMID to check for
+// aExePath the target exe path to check for, should be a long path where
+//          possible
+// aShortcutSubstring a substring to limit which shortcuts in aCSIDL are
+//                    inspected for a match. Only shortcuts whose filename
+//                    contains this substring will be considered
+// aShortcutPath outparam, set to matching shortcut path if NS_OK is returned.
+//
+// Returns
+//   NS_ERROR_FAILURE on errors before any shortcuts were loaded
+//   NS_ERROR_FILE_NOT_FOUND if no shortcuts matching aShortcutSubstring exist
+//   NS_ERROR_FILE_ALREADY_EXISTS if shortcuts were found but did not match
+//                                aAUMID or aExePath
+//   NS_OK if a matching shortcut is found
+static nsresult GetMatchingShortcut(int aCSIDL, const nsAString& aAUMID,
+                                    const wchar_t aExePath[MAXPATHLEN],
+                                    const nsAString& aShortcutSubstring,
+                                    /* out */ nsAutoString& aShortcutPath) {
+  nsresult result = NS_ERROR_FAILURE;
+
+  wchar_t folderPath[MAX_PATH] = {};
+  HRESULT hr = SHGetFolderPathW(nullptr, aCSIDL, nullptr, SHGFP_TYPE_CURRENT,
+                                folderPath);
+  if (NS_WARN_IF(FAILED(hr))) {
+    return NS_ERROR_FAILURE;
+  }
+  if (wcscat_s(folderPath, MAX_PATH, L"\\") != 0) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Get list of shortcuts in aCSIDL
+  nsAutoString pattern(folderPath);
+  pattern.AppendLiteral("*.lnk");
+
+  WIN32_FIND_DATAW findData = {};
+  HANDLE hFindFile = FindFirstFileW(pattern.get(), &findData);
+  if (hFindFile == INVALID_HANDLE_VALUE) {
+    Unused << NS_WARN_IF(GetLastError() != ERROR_FILE_NOT_FOUND);
+    return NS_ERROR_FILE_NOT_FOUND;
+  }
+  // Past this point we don't return until the end of the function,
+  // when FindClose() is called.
+
+  // todo: improve return values here
+  do {
+    // Skip any that don't contain aShortcutSubstring
+    // This is a case sensitive comparison, but that's probably fine for
+    // the vast majority of cases -- and certainly for all the ones where
+    // a shortcut was created by the installer.
+    if (StrStrIW(findData.cFileName, aShortcutSubstring.Data()) == NULL) {
+      continue;
+    }
+
+    nsAutoString path(folderPath);
+    path.Append(findData.cFileName);
+
+    // Create a shell link object for loading the shortcut
+    RefPtr<IShellLinkW> link;
+    HRESULT hr =
+        CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                         IID_IShellLinkW, getter_AddRefs(link));
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    // Load
+    RefPtr<IPersistFile> persist;
+    hr = link->QueryInterface(IID_IPersistFile, getter_AddRefs(persist));
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    hr = persist->Load(path.get(), STGM_READ);
+    if (FAILED(hr)) {
+      if (NS_WARN_IF(hr != HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))) {
+        // empty branch, result unchanged but warning issued
+      } else {
+        // If we've ever gotten past this block, result will already be
+        // NS_ERROR_FILE_ALREADY_EXISTS, which is a more accurate error
+        // than NS_ERROR_FILE_NOT_FOUND.
+        if (result != NS_ERROR_FILE_ALREADY_EXISTS) {
+          result = NS_ERROR_FILE_NOT_FOUND;
+        }
+      }
+      continue;
+    }
+    result = NS_ERROR_FILE_ALREADY_EXISTS;
+
+    // Check the AUMID
+    RefPtr<IPropertyStore> propStore;
+    hr = link->QueryInterface(IID_IPropertyStore, getter_AddRefs(propStore));
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    PROPVARIANT pv;
+    hr = propStore->GetValue(PKEY_AppUserModel_ID, &pv);
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    wchar_t storedAUMID[MAX_PATH];
+    hr = PropVariantToString(pv, storedAUMID, MAX_PATH);
+    PropVariantClear(&pv);
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    if (!aAUMID.Equals(storedAUMID)) {
+      continue;
+    }
+
+    // Check the exe path
+    static_assert(MAXPATHLEN == MAX_PATH);
+    wchar_t storedExePath[MAX_PATH] = {};
+    // With no flags GetPath gets a long path
+    hr = link->GetPath(storedExePath, ArrayLength(storedExePath), nullptr, 0);
+    if (FAILED(hr) || hr == S_FALSE) {
+      continue;
+    }
+    // Case insensitive path comparison
+    if (wcsnicmp(storedExePath, aExePath, MAXPATHLEN) == 0) {
+      aShortcutPath.Assign(path);
+      result = NS_OK;
+      break;
+    }
+  } while (FindNextFileW(hFindFile, &findData));
+
+  FindClose(hFindFile);
+
+  return result;
+}
+
+static nsresult FindMatchingShortcut(const nsAString& aAppUserModelId,
+                                     const nsAString& aShortcutSubstring,
+                                     const bool aPrivateBrowsing,
+                                     nsAutoString& aShortcutPath) {
+  wchar_t exePath[MAXPATHLEN] = {};
+  if (NS_WARN_IF(NS_FAILED(BinaryPath::GetLong(exePath)))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (aPrivateBrowsing) {
+    if (!PathRemoveFileSpecW(exePath)) {
+      return NS_ERROR_FAILURE;
+    }
+    if (!PathAppendW(exePath, L"private_browsing.exe")) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  int shortcutCSIDLs[] = {CSIDL_COMMON_PROGRAMS, CSIDL_PROGRAMS,
+                          CSIDL_COMMON_DESKTOPDIRECTORY,
+                          CSIDL_DESKTOPDIRECTORY};
+  for (int shortcutCSIDL : shortcutCSIDLs) {
+    // GetMatchingShortcut may fail when the exe path doesn't match, even
+    // if it refers to the same file. This should be rare, and the worst
+    // outcome would be failure to pin, so the risk is acceptable.
+    nsresult rv = GetMatchingShortcut(shortcutCSIDL, aAppUserModelId, exePath,
+                                      aShortcutSubstring, aShortcutPath);
+    if (NS_SUCCEEDED(rv)) {
+      return NS_OK;
+    }
+  }
+
+  return NS_ERROR_FILE_NOT_FOUND;
+}
+
+static bool HasMatchingShortcutImpl(const nsAString& aAppUserModelId,
+                                    const bool aPrivateBrowsing,
+                                    const nsAutoString& aShortcutSubstring) {
+  // unused by us, but required
+  nsAutoString shortcutPath;
+  nsresult rv = FindMatchingShortcut(aAppUserModelId, aShortcutSubstring,
+                                     aPrivateBrowsing, shortcutPath);
+  if (SUCCEEDED(rv)) {
+    return true;
+  }
+
+  return false;
+}
+
+NS_IMETHODIMP nsWindowsShellService::HasMatchingShortcut(
+    const nsAString& aAppUserModelId, const bool aPrivateBrowsing,
+    JSContext* aCx, dom::Promise** aPromise) {
+  if (!NS_IsMainThread()) {
+    return NS_ERROR_NOT_SAME_THREAD;
+  }
+
+  ErrorResult rv;
+  RefPtr<dom::Promise> promise =
+      dom::Promise::Create(xpc::CurrentNativeGlobal(aCx), rv);
+
+  if (MOZ_UNLIKELY(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  auto promiseHolder = MakeRefPtr<nsMainThreadPtrHolder<dom::Promise>>(
+      "HasMatchingShortcut promise", promise);
+
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction(
+          "HasMatchingShortcut",
+          [aAppUserModelId = nsString{aAppUserModelId}, aPrivateBrowsing,
+           promiseHolder = std::move(promiseHolder)] {
+            bool rv = false;
+            HRESULT hr = CoInitialize(nullptr);
+
+            if (SUCCEEDED(hr)) {
+              nsAutoString shortcutSubstring;
+              shortcutSubstring.AssignLiteral(MOZ_APP_DISPLAYNAME);
+              rv = HasMatchingShortcutImpl(aAppUserModelId, aPrivateBrowsing,
+                                           shortcutSubstring);
+              CoUninitialize();
+            }
+
+            NS_DispatchToMainThread(NS_NewRunnableFunction(
+                "HasMatchingShortcut callback",
+                [rv, promiseHolder = std::move(promiseHolder)] {
+                  dom::Promise* promise = promiseHolder.get()->get();
+
+                  promise->MaybeResolve(rv);
+                }));
+          }),
+      NS_DISPATCH_EVENT_MAY_BLOCK);
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+static nsresult PinCurrentAppToTaskbarWin7(bool aCheckOnly,
+                                           nsAutoString aShortcutPath) {
+  nsModuleHandle shellInst(LoadLibraryW(L"shell32.dll"));
+
+  RefPtr<IShellWindows> shellWindows;
+  HRESULT hr =
+      ::CoCreateInstance(CLSID_ShellWindows, nullptr, CLSCTX_LOCAL_SERVER,
+                         IID_IShellWindows, getter_AddRefs(shellWindows));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  // 1. Find the shell view for the desktop.
+  _variant_t loc(int(CSIDL_DESKTOP));
+  _variant_t empty;
+  long hwnd;
+  RefPtr<IDispatch> dispDesktop;
+  hr = shellWindows->FindWindowSW(&loc, &empty, SWC_DESKTOP, &hwnd,
+                                  SWFO_NEEDDISPATCH,
+                                  getter_AddRefs(dispDesktop));
+  if (FAILED(hr) || hr == S_FALSE) return NS_ERROR_FAILURE;
+
+  RefPtr<IServiceProvider> servProv;
+  hr = dispDesktop->QueryInterface(IID_IServiceProvider,
+                                   getter_AddRefs(servProv));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  RefPtr<IShellBrowser> browser;
+  hr = servProv->QueryService(SID_STopLevelBrowser, IID_IShellBrowser,
+                              getter_AddRefs(browser));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  RefPtr<IShellView> activeShellView;
+  hr = browser->QueryActiveShellView(getter_AddRefs(activeShellView));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  // 2. Get the automation object for the desktop.
+  RefPtr<IDispatch> dispView;
+  hr = activeShellView->GetItemObject(SVGIO_BACKGROUND, IID_IDispatch,
+                                      getter_AddRefs(dispView));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  RefPtr<IShellFolderViewDual> folderView;
+  hr = dispView->QueryInterface(IID_IShellFolderViewDual,
+                                getter_AddRefs(folderView));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  // 3. Get the interface to IShellDispatch
+  RefPtr<IDispatch> dispShell;
+  hr = folderView->get_Application(getter_AddRefs(dispShell));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  RefPtr<IShellDispatch2> shellDisp;
+  hr =
+      dispShell->QueryInterface(IID_IShellDispatch2, getter_AddRefs(shellDisp));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  wchar_t shortcutDir[MAX_PATH + 1];
+  wcscpy_s(shortcutDir, MAX_PATH + 1, aShortcutPath.get());
+  if (!PathRemoveFileSpecW(shortcutDir)) return NS_ERROR_FAILURE;
+
+  VARIANT dir;
+  dir.vt = VT_BSTR;
+  BStrPtr bstrShortcutDir = BStrPtr(SysAllocString(shortcutDir));
+  if (bstrShortcutDir.get() == NULL) return NS_ERROR_FAILURE;
+  dir.bstrVal = bstrShortcutDir.get();
+
+  RefPtr<Folder> folder;
+  hr = shellDisp->NameSpace(dir, getter_AddRefs(folder));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  wchar_t linkName[MAX_PATH + 1];
+  wcscpy_s(linkName, MAX_PATH + 1, aShortcutPath.get());
+  PathStripPathW(linkName);
+  BStrPtr bstrLinkName = BStrPtr(SysAllocString(linkName));
+  if (bstrLinkName.get() == NULL) return NS_ERROR_FAILURE;
+
+  RefPtr<FolderItem> folderItem;
+  hr = folder->ParseName(bstrLinkName.get(), getter_AddRefs(folderItem));
+  if (FAILED(hr) || !folderItem) return NS_ERROR_FAILURE;
+
+  RefPtr<FolderItemVerbs> verbs;
+  hr = folderItem->Verbs(getter_AddRefs(verbs));
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  long count;
+  hr = verbs->get_Count(&count);
+  if (FAILED(hr)) return NS_ERROR_FAILURE;
+
+  WCHAR verbName[100];
+  if (!LoadStringW(shellInst.get(), PIN_TO_TASKBAR_SHELL_VERB, verbName,
+                   ARRAYSIZE(verbName))) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  VARIANT v;
+  v.vt = VT_I4;
+  BStrPtr name;
+  for (long i = 0; i < count; ++i) {
+    RefPtr<FolderItemVerb> fiVerb;
+    v.lVal = i;
+    hr = verbs->Item(v, getter_AddRefs(fiVerb));
+    if (FAILED(hr)) {
+      continue;
+    }
+
+    BSTR tmpName;
+    hr = fiVerb->get_Name(&tmpName);
+    if (FAILED(hr)) {
+      continue;
+    }
+    name = BStrPtr(tmpName);
+    if (!wcscmp((WCHAR*)name.get(), verbName)) {
+      if (aCheckOnly) {
+        // we've done as much as we can without actually
+        // changing anything
+        return NS_OK;
+      }
+
+      hr = fiVerb->DoIt();
+      if (SUCCEEDED(hr)) {
+        return NS_OK;
+      }
+    }
+  }
+
+  // if we didn't return in the block above, something failed
+  return NS_ERROR_FAILURE;
+}
+
+static nsresult PinCurrentAppToTaskbarWin10(bool aCheckOnly,
+                                            nsAutoString aShortcutPath) {
+  // This enum is likely only used for Windows telemetry, INT_MAX is chosen to
+  // avoid confusion with existing uses.
+  enum PINNEDLISTMODIFYCALLER { PLMC_INT_MAX = INT_MAX };
+
+  // The types below, and the idea of using IPinnedList3::Modify,
+  // are thanks to Gee Law <https://geelaw.blog/entries/msedge-pins/>
+  static constexpr GUID CLSID_TaskbandPin = {
+      0x90aa3a4e,
+      0x1cba,
+      0x4233,
+      {0xb8, 0xbb, 0x53, 0x57, 0x73, 0xd4, 0x84, 0x49}};
+
+  static constexpr GUID IID_IPinnedList3 = {
+      0x0dd79ae2,
+      0xd156,
+      0x45d4,
+      {0x9e, 0xeb, 0x3b, 0x54, 0x97, 0x69, 0xe9, 0x40}};
+
+  struct IPinnedList3Vtbl;
+  struct IPinnedList3 {
+    IPinnedList3Vtbl* vtbl;
+  };
+
+  typedef ULONG STDMETHODCALLTYPE ReleaseFunc(IPinnedList3 * that);
+  typedef HRESULT STDMETHODCALLTYPE ModifyFunc(
+      IPinnedList3 * that, PCIDLIST_ABSOLUTE unpin, PCIDLIST_ABSOLUTE pin,
+      PINNEDLISTMODIFYCALLER caller);
+
+  struct IPinnedList3Vtbl {
+    void* QueryInterface;  // 0
+    void* AddRef;          // 1
+    ReleaseFunc* Release;  // 2
+    void* Other[13];       // 3-15
+    ModifyFunc* Modify;    // 16
+  };
+
+  struct ILFreeDeleter {
+    void operator()(LPITEMIDLIST aPtr) {
+      if (aPtr) {
+        ILFree(aPtr);
+      }
+    }
+  };
+
+  mozilla::UniquePtr<__unaligned ITEMIDLIST, ILFreeDeleter> path(
+      ILCreateFromPathW(aShortcutPath.get()));
+  if (NS_WARN_IF(!path)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  IPinnedList3* pinnedList = nullptr;
+  HRESULT hr =
+      CoCreateInstance(CLSID_TaskbandPin, nullptr, CLSCTX_INPROC_SERVER,
+                       IID_IPinnedList3, (void**)&pinnedList);
+  if (FAILED(hr) || !pinnedList) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (!aCheckOnly) {
+    hr =
+        pinnedList->vtbl->Modify(pinnedList, nullptr, path.get(), PLMC_INT_MAX);
+  }
+
+  pinnedList->vtbl->Release(pinnedList);
+
+  if (FAILED(hr)) {
+    return NS_ERROR_FAILURE;
+  } else {
+    return NS_OK;
+  }
+}
+
+static nsresult PinCurrentAppToTaskbarImpl(
+    bool aCheckOnly, bool aPrivateBrowsing, const nsAString& aAppUserModelId,
+    const nsAString& aShortcutName, const nsAString& aShortcutSubstring,
+    nsIFile* aShortcutsLogDir, nsIFile* aGreDir, nsIFile* aProgramsDir) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      !NS_IsMainThread(),
+      "PinCurrentAppToTaskbarImpl should be called off main thread only");
+
+  nsAutoString shortcutPath;
+  nsresult rv = FindMatchingShortcut(aAppUserModelId, aShortcutSubstring,
+                                     aPrivateBrowsing, shortcutPath);
+  if (NS_FAILED(rv)) {
+    shortcutPath.Truncate();
+  }
+  if (shortcutPath.IsEmpty()) {
+    if (aCheckOnly) {
+      // Later checks rely on a shortcut already existing.
+      // We don't want to create a shortcut in check only mode
+      // so the best we can do is assume those parts will work.
+      return NS_OK;
+    }
+
+    nsAutoString linkName(aShortcutName);
+
+    nsCOMPtr<nsIFile> exeFile(aGreDir);
+    if (aPrivateBrowsing) {
+      nsAutoString pbExeStr(PRIVATE_BROWSING_BINARY);
+      nsresult rv = exeFile->Append(pbExeStr);
+      if (!NS_SUCCEEDED(rv)) {
+        return NS_ERROR_FAILURE;
+      }
+    } else {
+      wchar_t exePath[MAXPATHLEN] = {};
+      if (NS_WARN_IF(NS_FAILED(BinaryPath::GetLong(exePath)))) {
+        return NS_ERROR_FAILURE;
+      }
+      nsAutoString exeStr(exePath);
+      nsresult rv = NS_NewLocalFile(exeStr, true, getter_AddRefs(exeFile));
+      if (!NS_SUCCEEDED(rv)) {
+        return NS_ERROR_FILE_NOT_FOUND;
+      }
+    }
+
+    nsCOMPtr<nsIFile> shortcutFile(aProgramsDir);
+    shortcutFile->Append(aShortcutName);
+    shortcutPath.Assign(shortcutFile->NativePath());
+
+    nsTArray<nsString> arguments;
+    rv = CreateShortcutImpl(exeFile, arguments, aShortcutName, exeFile,
+                            // Icon indexes are defined as Resource IDs, but
+                            // CreateShortcutImpl needs an index.
+                            IDI_APPICON - 1, aAppUserModelId, FOLDERID_Programs,
+                            linkName, shortcutFile->NativePath(),
+                            aShortcutsLogDir);
+    if (!NS_SUCCEEDED(rv)) {
+      return NS_ERROR_FILE_NOT_FOUND;
+    }
+  }
+
+  if (IsWin10OrLater()) {
+    return PinCurrentAppToTaskbarWin10(aCheckOnly, shortcutPath);
+  } else {
+    return PinCurrentAppToTaskbarWin7(aCheckOnly, shortcutPath);
+  }
+}
+
+static nsresult PinCurrentAppToTaskbarAsyncImpl(bool aCheckOnly,
+                                                bool aPrivateBrowsing,
+                                                JSContext* aCx,
+                                                dom::Promise** aPromise) {
+  if (!NS_IsMainThread()) {
+    return NS_ERROR_NOT_SAME_THREAD;
+  }
+
+  // First available on 1809
+  if (IsWin10OrLater() && !IsWin10Sep2018UpdateOrLater()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  ErrorResult rv;
+  RefPtr<dom::Promise> promise =
+      dom::Promise::Create(xpc::CurrentNativeGlobal(aCx), rv);
+
+  if (MOZ_UNLIKELY(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  nsAutoString aumid;
+  if (NS_WARN_IF(!mozilla::widget::WinTaskbar::GenerateAppUserModelID(
+          aumid, aPrivateBrowsing))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // NOTE: In the installer, non-private shortcuts are named
+  // "${BrandShortName}.lnk". This is set from MOZ_APP_DISPLAYNAME in
+  // defines.nsi.in. (Except in dev edition where it's explicitly set to
+  // "Firefox Developer Edition" in branding.nsi, which matches
+  // MOZ_APP_DISPLAYNAME in aurora/configure.sh.)
+  //
+  // If this changes, we could expand this to check shortcuts_log.ini,
+  // which records the name of the shortcuts as created by the installer.
+  //
+  // Private shortcuts are not created by the installer (they're created
+  // upon user request, ultimately by CreateShortcutImpl, and recorded in
+  // a separate shortcuts log. As with non-private shortcuts they have a known
+  // name - so there's no need to look through logs to find them.
+  nsAutoString shortcutName;
+  if (aPrivateBrowsing) {
+    nsTArray<nsCString> resIds = {
+        "branding/brand.ftl"_ns,
+        "browser/browser.ftl"_ns,
+    };
+    RefPtr<Localization> l10n = Localization::Create(resIds, true);
+    nsAutoCString pbStr;
+    IgnoredErrorResult rv;
+    l10n->FormatValueSync("private-browsing-shortcut-text-2"_ns, {}, pbStr, rv);
+    shortcutName.Append(NS_ConvertUTF8toUTF16(pbStr));
+    shortcutName.AppendLiteral(".lnk");
+  } else {
+    shortcutName.AppendLiteral(MOZ_APP_DISPLAYNAME ".lnk");
+  }
+
+  nsCOMPtr<nsIFile> greDir, updRoot, programsDir, shortcutsLogDir;
+  nsresult nsrv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(greDir));
+  NS_ENSURE_SUCCESS(nsrv, nsrv);
+  nsrv = NS_GetSpecialDirectory(XRE_UPDATE_ROOT_DIR, getter_AddRefs(updRoot));
+  NS_ENSURE_SUCCESS(nsrv, nsrv);
+  rv = NS_GetSpecialDirectory(NS_WIN_PROGRAMS_DIR, getter_AddRefs(programsDir));
+  NS_ENSURE_SUCCESS(nsrv, nsrv);
+  nsrv = updRoot->GetParent(getter_AddRefs(shortcutsLogDir));
+  NS_ENSURE_SUCCESS(nsrv, nsrv);
+
+  auto promiseHolder = MakeRefPtr<nsMainThreadPtrHolder<dom::Promise>>(
+      "CheckPinCurrentAppToTaskbarAsync promise", promise);
+
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction(
+          "CheckPinCurrentAppToTaskbarAsync",
+          [aCheckOnly, aPrivateBrowsing, shortcutName, aumid = nsString{aumid},
+           shortcutsLogDir, greDir, programsDir,
+           promiseHolder = std::move(promiseHolder)] {
+            nsresult rv = NS_ERROR_FAILURE;
+            HRESULT hr = CoInitialize(nullptr);
+
+            if (SUCCEEDED(hr)) {
+              nsAutoString shortcutSubstring;
+              shortcutSubstring.AssignLiteral(MOZ_APP_DISPLAYNAME);
+              rv = PinCurrentAppToTaskbarImpl(
+                  aCheckOnly, aPrivateBrowsing, aumid, shortcutName,
+                  shortcutSubstring, shortcutsLogDir.get(), greDir.get(),
+                  programsDir.get());
+              CoUninitialize();
+            }
+
+            NS_DispatchToMainThread(NS_NewRunnableFunction(
+                "CheckPinCurrentAppToTaskbarAsync callback",
+                [rv, promiseHolder = std::move(promiseHolder)] {
+                  dom::Promise* promise = promiseHolder.get()->get();
+
+                  if (NS_SUCCEEDED(rv)) {
+                    promise->MaybeResolveWithUndefined();
+                  } else {
+                    promise->MaybeReject(rv);
+                  }
+                }));
+          }),
+      NS_DISPATCH_EVENT_MAY_BLOCK);
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::PinCurrentAppToTaskbarAsync(bool aPrivateBrowsing,
+                                                   JSContext* aCx,
+                                                   dom::Promise** aPromise) {
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=1712628 tracks implementing
+  // this for MSIX packages.
+  if (widget::WinUtils::HasPackageIdentity()) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  return PinCurrentAppToTaskbarAsyncImpl(
+      /* aCheckOnly */ false, aPrivateBrowsing, aCx, aPromise);
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::CheckPinCurrentAppToTaskbarAsync(
+    bool aPrivateBrowsing, JSContext* aCx, dom::Promise** aPromise) {
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=1712628 tracks implementing
+  // this for MSIX packages.
+  if (widget::WinUtils::HasPackageIdentity()) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  return PinCurrentAppToTaskbarAsyncImpl(
+      /* aCheckOnly = */ true, aPrivateBrowsing, aCx, aPromise);
+}
+
+static bool IsCurrentAppPinnedToTaskbarSync(const nsAutoString& aumid) {
+  // There are two shortcut targets that we created. One always matches the
+  // binary we're running as (eg: firefox.exe). The other is the wrapper
+  // for launching in Private Browsing mode. We need to inspect shortcuts
+  // that point at either of these to accurately judge whether or not
+  // the app is pinned with the given AUMID.
+  wchar_t exePath[MAXPATHLEN] = {};
+  wchar_t pbExePath[MAXPATHLEN] = {};
+
+  if (NS_WARN_IF(NS_FAILED(BinaryPath::GetLong(exePath)))) {
+    return false;
+  }
+
+  wcscpy_s(pbExePath, MAXPATHLEN, exePath);
+  if (!PathRemoveFileSpecW(pbExePath)) {
+    return false;
+  }
+  if (!PathAppendW(pbExePath, L"private_browsing.exe")) {
+    return false;
+  }
+
+  wchar_t folderChars[MAX_PATH] = {};
+  HRESULT hr = SHGetFolderPathW(nullptr, CSIDL_APPDATA, nullptr,
+                                SHGFP_TYPE_CURRENT, folderChars);
+  if (NS_WARN_IF(FAILED(hr))) {
+    return false;
+  }
+
+  nsAutoString folder;
+  folder.Assign(folderChars);
+  if (NS_WARN_IF(folder.IsEmpty())) {
+    return false;
+  }
+  if (folder[folder.Length() - 1] != '\\') {
+    folder.AppendLiteral("\\");
+  }
+  folder.AppendLiteral(
+      "Microsoft\\Internet Explorer\\Quick Launch\\User Pinned\\TaskBar");
+  nsAutoString pattern;
+  pattern.Assign(folder);
+  pattern.AppendLiteral("\\*.lnk");
+
+  WIN32_FIND_DATAW findData = {};
+  HANDLE hFindFile = FindFirstFileW(pattern.get(), &findData);
+  if (hFindFile == INVALID_HANDLE_VALUE) {
+    Unused << NS_WARN_IF(GetLastError() != ERROR_FILE_NOT_FOUND);
+    return false;
+  }
+  // Past this point we don't return until the end of the function,
+  // when FindClose() is called.
+
+  // Check all shortcuts until a match is found
+  bool isPinned = false;
+  do {
+    nsAutoString fileName;
+    fileName.Assign(folder);
+    fileName.AppendLiteral("\\");
+    fileName.Append(findData.cFileName);
+
+    // Create a shell link object for loading the shortcut
+    RefPtr<IShellLinkW> link;
+    HRESULT hr =
+        CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                         IID_IShellLinkW, getter_AddRefs(link));
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    // Load
+    RefPtr<IPersistFile> persist;
+    hr = link->QueryInterface(IID_IPersistFile, getter_AddRefs(persist));
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    hr = persist->Load(fileName.get(), STGM_READ);
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    // Check the exe path
+    static_assert(MAXPATHLEN == MAX_PATH);
+    wchar_t storedExePath[MAX_PATH] = {};
+    // With no flags GetPath gets a long path
+    hr = link->GetPath(storedExePath, ArrayLength(storedExePath), nullptr, 0);
+    if (FAILED(hr) || hr == S_FALSE) {
+      continue;
+    }
+    // Case insensitive path comparison
+    // NOTE: Because this compares the path directly, it is possible to
+    // have a false negative mismatch.
+    if (wcsnicmp(storedExePath, exePath, MAXPATHLEN) == 0 ||
+        wcsnicmp(storedExePath, pbExePath, MAXPATHLEN) == 0) {
+      RefPtr<IPropertyStore> propStore;
+      hr = link->QueryInterface(IID_IPropertyStore, getter_AddRefs(propStore));
+      if (NS_WARN_IF(FAILED(hr))) {
+        continue;
+      }
+
+      PROPVARIANT pv;
+      hr = propStore->GetValue(PKEY_AppUserModel_ID, &pv);
+      if (NS_WARN_IF(FAILED(hr))) {
+        continue;
+      }
+
+      wchar_t storedAUMID[MAX_PATH];
+      hr = PropVariantToString(pv, storedAUMID, MAX_PATH);
+      PropVariantClear(&pv);
+      if (NS_WARN_IF(FAILED(hr))) {
+        continue;
+      }
+
+      if (aumid.Equals(storedAUMID)) {
+        isPinned = true;
+        break;
+      }
+    }
+  } while (FindNextFileW(hFindFile, &findData));
+
+  FindClose(hFindFile);
+
+  return isPinned;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::IsCurrentAppPinnedToTaskbarAsync(
+    const nsAString& aumid, JSContext* aCx, /* out */ dom::Promise** aPromise) {
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=1712628 tracks implementing
+  // this for MSIX packages.
+  if (widget::WinUtils::HasPackageIdentity()) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  if (!NS_IsMainThread()) {
+    return NS_ERROR_NOT_SAME_THREAD;
+  }
+
+  ErrorResult rv;
+  RefPtr<dom::Promise> promise =
+      dom::Promise::Create(xpc::CurrentNativeGlobal(aCx), rv);
+  if (MOZ_UNLIKELY(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  // A holder to pass the promise through the background task and back to
+  // the main thread when finished.
+  auto promiseHolder = MakeRefPtr<nsMainThreadPtrHolder<dom::Promise>>(
+      "IsCurrentAppPinnedToTaskbarAsync promise", promise);
+
+  // nsAString can't be captured by a lambda because it does not have a
+  // public copy constructor
+  nsAutoString capturedAumid(aumid);
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction(
+          "IsCurrentAppPinnedToTaskbarAsync",
+          [capturedAumid, promiseHolder = std::move(promiseHolder)] {
+            bool isPinned = false;
+
+            HRESULT hr = CoInitialize(nullptr);
+            if (SUCCEEDED(hr)) {
+              isPinned = IsCurrentAppPinnedToTaskbarSync(capturedAumid);
+              CoUninitialize();
+            }
+
+            // Dispatch back to the main thread to resolve the promise.
+            NS_DispatchToMainThread(NS_NewRunnableFunction(
+                "IsCurrentAppPinnedToTaskbarAsync callback",
+                [isPinned, promiseHolder = std::move(promiseHolder)] {
+                  promiseHolder.get()->get()->MaybeResolve(isPinned);
+                }));
+          }),
+      NS_DISPATCH_EVENT_MAY_BLOCK);
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWindowsShellService::ClassifyShortcut(const nsAString& aPath,
+                                        nsAString& aResult) {
+  aResult.Truncate();
+
+  nsAutoString shortcutPath(PromiseFlatString(aPath));
+
+  // NOTE: On Windows 7, Start Menu pin shortcuts are stored under
+  // "<FOLDERID_User Pinned>\StartMenu", but on Windows 10 they are just normal
+  // Start Menu shortcuts. These both map to "StartMenu" for consistency,
+  // rather than having a separate "StartMenuPins" which would only apply on
+  // Win7.
+  struct {
+    KNOWNFOLDERID folderId;
+    const char16_t* postfix;
+    const char16_t* classification;
+  } folders[] = {{FOLDERID_CommonStartMenu, u"\\", u"StartMenu"},
+                 {FOLDERID_StartMenu, u"\\", u"StartMenu"},
+                 {FOLDERID_PublicDesktop, u"\\", u"Desktop"},
+                 {FOLDERID_Desktop, u"\\", u"Desktop"},
+                 {FOLDERID_UserPinned, u"\\TaskBar\\", u"Taskbar"},
+                 {FOLDERID_UserPinned, u"\\StartMenu\\", u"StartMenu"}};
+
+  for (size_t i = 0; i < ArrayLength(folders); ++i) {
+    nsAutoString knownPath;
+
+    // These flags are chosen to avoid I/O, see bug 1363398.
+    DWORD flags =
+        KF_FLAG_SIMPLE_IDLIST | KF_FLAG_DONT_VERIFY | KF_FLAG_NO_ALIAS;
+    PWSTR rawPath = nullptr;
+
+    if (FAILED(SHGetKnownFolderPath(folders[i].folderId, flags, nullptr,
+                                    &rawPath))) {
+      continue;
+    }
+
+    knownPath = nsDependentString(rawPath);
+    CoTaskMemFree(rawPath);
+
+    knownPath.Append(folders[i].postfix);
+    // Check if the shortcut path starts with the shell folder path.
+    if (wcsnicmp(shortcutPath.get(), knownPath.get(), knownPath.Length()) ==
+        0) {
+      aResult.Assign(folders[i].classification);
+      nsTArray<nsCString> resIds = {
+          "branding/brand.ftl"_ns,
+          "browser/browser.ftl"_ns,
+      };
+      RefPtr<Localization> l10n = Localization::Create(resIds, true);
+      nsAutoCString pbStr;
+      IgnoredErrorResult rv;
+      l10n->FormatValueSync("private-browsing-shortcut-text-2"_ns, {}, pbStr,
+                            rv);
+      NS_ConvertUTF8toUTF16 widePbStr(pbStr);
+      if (wcsstr(shortcutPath.get(), widePbStr.get())) {
+        aResult.AppendLiteral("Private");
+      }
+      return NS_OK;
+    }
+  }
+
+  // Nothing found, aResult is already "".
+  return NS_OK;
+}
+
+nsWindowsShellService::nsWindowsShellService() {}
+
+nsWindowsShellService::~nsWindowsShellService() {}