Bug 1657073. Make sure to destroy direct manipulation objects before …

…we clear our HWND pointer. r=kats

Otherwise when we try to call Deactivate on the direct manipulation manager (to balance the Activate call) we won't have the HWND pointer and so it won't balance and we will leak.

We call DestroyDirectManipulation in nsWindow::Destroy but it looks like nsWindow::OnDestroy can be called before nsWindow::Destroy.

Differential Revision: https://phabricator.services.mozilla.com/D85835

widget/windows/nsWindow.cpp

@@ -7347,6 +7347,8 @@ void nsWindow::OnDestroy() {
   mWidgetListener = nullptr;
   mAttachedWidgetListener = nullptr;
 
+  DestroyDirectManipulation();
+
   if (mWnd == mLastKillFocusWindow) {
     mLastKillFocusWindow = nullptr;
   }