Bug 1156182 - Ensure nsWindow::Destroy() is called before destroying mPresentLock to avoid a race with the compositor thread. r=Bas

widget/windows/nsWindow.cpp

@@ -409,10 +409,9 @@ nsWindow::~nsWindow()
   mInDtor = true;
 
   // If the widget was released without calling Destroy() then the native window still
-  // exists, and we need to destroy it. This will also result in a call to OnDestroy.
+  // exists, and we need to destroy it.
-  //
+  // Destroy() will early-return if it was already called. In any case it is important
-  // XXX How could this happen???
+  // to call it before destroying mPresentLock (cf. 1156182).
-  if (nullptr != mWnd)
   Destroy();
 
   // Free app icon resources.  This must happen after `OnDestroy` (see bug 708033).