--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -1879,17 +1879,51 @@ XRE_GetBinaryPath(nsIFile* *aResult)
   return mozilla::BinaryPath::GetFile(aResult);
 }
 
 #ifdef XP_WIN
 #include "nsWindowsRestart.cpp"
 #include <shellapi.h>
 
 typedef BOOL (WINAPI* SetProcessDEPPolicyFunc)(DWORD dwFlags);
-#endif
+
+#define PREF_WIN_REGISTER_APPLICATION_RESTART "toolkit.winRegisterApplicationRestart"
+
+static void
+RegisterApplicationRestartChanged(const char* aPref, void* aData) {
+  if (Preferences::GetBool(PREF_WIN_REGISTER_APPLICATION_RESTART, true)) {
+    // Make the command line to use when restarting
+    wchar_t* restartCommandLine = nullptr;
+    if (gRestartArgc > 1) {
+      // excludes argv[0] because RegisterApplicationRestart adds the
+      // executable name
+      wchar_t** restartArgvConverted =
+        AllocConvertUTF8toUTF16Strings(gRestartArgc - 1, gRestartArgv + 1);
+
+      if (restartArgvConverted) {
+        restartCommandLine = MakeCommandLine(gRestartArgc - 1, restartArgvConverted);
+        FreeAllocStrings(gRestartArgc - 1, restartArgvConverted);
+      }
+    } else {
+      restartCommandLine = (wchar_t*) malloc(sizeof(wchar_t));
+      restartCommandLine[0] = L'\0';
+    }
+
+    if (restartCommandLine) {
+      // Flags RESTART_NO_PATCH and RESTART_NO_REBOOT are not set, so we
+      // should be restarted if terminated by an update or restart.
+      ::RegisterApplicationRestart(restartCommandLine, RESTART_NO_CRASH |
+                                                       RESTART_NO_HANG);
+      free(restartCommandLine);
+    }
+  } else {
+    ::UnregisterApplicationRestart();
+  }
+}
+#endif // XP_WIN
 
 // If aBlankCommandLine is true, then the application will be launched with a
 // blank command line instead of being launched with the same command line that
 // it was initially started with.
 static nsresult LaunchChild(nsINativeAppSupport* aNative,
                             bool aBlankCommandLine = false)
 {
   aNative->Quit(); // release DDE mutex, if we're holding it
@@ -4730,16 +4764,21 @@ XREMain::XRE_mainRun()
   SaveToEnv("NO_EM_RESTART=");
   SaveToEnv("XUL_APP_FILE=");
   SaveToEnv("XRE_BINARY_PATH=");
 
   if (!mShuttingDown) {
     rv = appStartup->CreateHiddenWindow();
     NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);
 
+#ifdef XP_WIN32
+    Preferences::RegisterCallbackAndCall(RegisterApplicationRestartChanged,
+                                         PREF_WIN_REGISTER_APPLICATION_RESTART);
+#endif
+
 #if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_WIDGET_GTK)
     nsGTKToolkit* toolkit = nsGTKToolkit::GetToolkit();
     if (toolkit && !mDesktopStartupID.IsEmpty()) {
       toolkit->SetDesktopStartupID(mDesktopStartupID);
     }
     // Clear the environment variable so it won't be inherited by
     // child processes and confuse things.
     g_unsetenv ("DESKTOP_STARTUP_ID");

--- a/toolkit/xre/nsWindowsRestart.cpp
+++ b/toolkit/xre/nsWindowsRestart.cpp
@@ -108,18 +108,16 @@ static wchar_t* ArgToString(wchar_t *d, 
   }
 
   return d;
 }
 
 /**
  * Creates a command line from a list of arguments. The returned
  * string is allocated with "malloc" and should be "free"d.
- *
- * argv is UTF8
  */
 wchar_t*
 MakeCommandLine(int argc, wchar_t **argv)
 {
   int i;
   int len = 0;
 
   // The + 1 of the last argument handles the allocation for null termination
@@ -173,16 +171,32 @@ FreeAllocStrings(int argc, wchar_t **arg
   while (argc) {
     --argc;
     delete [] argv[argc];
   }
 
   delete [] argv;
 }
 
+static wchar_t**
+AllocConvertUTF8toUTF16Strings(int argc, char **argv)
+{
+  wchar_t **argvConverted = new wchar_t*[argc];
+  if (!argvConverted)
+    return nullptr;
+
+  for (int i = 0; i < argc; ++i) {
+    argvConverted[i] = reinterpret_cast<wchar_t*>(AllocConvertUTF8toUTF16(argv[i]));
+    if (!argvConverted[i]) {
+      FreeAllocStrings(i, argvConverted);
+      return nullptr;
+    }
+  }
+  return argvConverted;
+}
 
 
 /**
  * Launch a child process with the specified arguments.
  * @note argv[0] is ignored
  * @note The form of this function that takes char **argv expects UTF-8
  */
 
@@ -193,28 +207,20 @@ WinLaunchChild(const wchar_t *exePath,
                HANDLE *hProcess = nullptr);
 
 BOOL
 WinLaunchChild(const wchar_t *exePath,
                int argc, char **argv,
                HANDLE userToken,
                HANDLE *hProcess)
 {
-  wchar_t** argvConverted = new wchar_t*[argc];
+  wchar_t **argvConverted = AllocConvertUTF8toUTF16Strings(argc, argv);
   if (!argvConverted)
     return FALSE;
 
-  for (int i = 0; i < argc; ++i) {
-      argvConverted[i] = reinterpret_cast<wchar_t*>(AllocConvertUTF8toUTF16(argv[i]));
-    if (!argvConverted[i]) {
-      FreeAllocStrings(i, argvConverted);
-      return FALSE;
-    }
-  }
-
   BOOL ok = WinLaunchChild(exePath, argc, argvConverted, userToken, hProcess);
   FreeAllocStrings(argc, argvConverted);
   return ok;
 }
 
 BOOL
 WinLaunchChild(const wchar_t *exePath,
                int argc,

--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -5176,31 +5176,39 @@ nsWindow::ProcessMessage(UINT msg, WPARA
       /* We don't do this for win10 glass with a custom titlebar,
        * in order to avoid the caption buttons breaking. */
       !(IsWin10OrLater() && HasGlass()) &&
       DwmDefWindowProc(mWnd, msg, wParam, lParam, &dwmHitResult)) {
     *aRetValue = dwmHitResult;
     return true;
   }
 
+  static const char kRestartPrefName[] = "toolkit.winRegisterApplicationRestart";
+
   // (Large blocks of code should be broken out into OnEvent handlers.)
   switch (msg) {
     // WM_QUERYENDSESSION must be handled by all windows.
     // Otherwise Windows thinks the window can just be killed at will.
     case WM_QUERYENDSESSION:
       if (sCanQuit == TRI_UNKNOWN)
       {
         // Ask if it's ok to quit, and store the answer until we
         // get WM_ENDSESSION signaling the round is complete.
         nsCOMPtr<nsIObserverService> obsServ =
           mozilla::services::GetObserverService();
         nsCOMPtr<nsISupportsPRBool> cancelQuit =
           do_CreateInstance(NS_SUPPORTS_PRBOOL_CONTRACTID);
         cancelQuit->SetData(false);
-        obsServ->NotifyObservers(cancelQuit, "quit-application-requested", nullptr);
+
+        const char16_t* quitType = nullptr;
+        if (Preferences::GetBool(kRestartPrefName, true)) {
+          quitType = u"restart";
+        }
+
+        obsServ->NotifyObservers(cancelQuit, "quit-application-requested", quitType);
 
         bool abortQuit;
         cancelQuit->GetData(&abortQuit);
         sCanQuit = abortQuit ? TRI_FALSE : TRI_TRUE;
       }
       *aRetValue = sCanQuit ? TRUE : FALSE;
       result = true;
       break;
@@ -5221,19 +5229,24 @@ nsWindow::ProcessMessage(UINT msg, WPARA
         // Let's fake a shutdown sequence without actually closing windows etc.
         // to avoid Windows killing us in the middle. A proper shutdown would
         // require having a chance to pump some messages. Unfortunately
         // Windows won't let us do that. Bug 212316.
         nsCOMPtr<nsIObserverService> obsServ =
           mozilla::services::GetObserverService();
         const char16_t* context = u"shutdown-persist";
         const char16_t* syncShutdown = u"syncShutdown";
+        const char16_t* quitType = nullptr;
+        if (Preferences::GetBool(kRestartPrefName, true)) {
+          quitType = u"restart";
+        }
+
         obsServ->NotifyObservers(nullptr, "quit-application-granted", syncShutdown);
         obsServ->NotifyObservers(nullptr, "quit-application-forced", nullptr);
-        obsServ->NotifyObservers(nullptr, "quit-application", nullptr);
+        obsServ->NotifyObservers(nullptr, "quit-application", quitType);
         obsServ->NotifyObservers(nullptr, "profile-change-net-teardown", context);
         obsServ->NotifyObservers(nullptr, "profile-change-teardown", context);
         obsServ->NotifyObservers(nullptr, "profile-before-change", context);
         obsServ->NotifyObservers(nullptr, "profile-before-change-qm", context);
         obsServ->NotifyObservers(nullptr, "profile-before-change-telemetry", context);
         ExitThisProcessSafely();
       }
       sCanQuit = TRI_UNKNOWN;