Deregister window classes

ui/gfx/win/window_impl.h

Index: ui/gfx/win/window_impl.h
diff --git a/ui/gfx/win/window_impl.h b/ui/gfx/win/window_impl.h
index 8206562935ff1ca8eb6c685231a58f854c876192..348253671f4f6fa0c42bf9c447d0ecc01e5ddbc2 100644
--- a/ui/gfx/win/window_impl.h
+++ b/ui/gfx/win/window_impl.h
@@ -41,6 +41,11 @@ class GFX_EXPORT WindowImpl : public MessageMapInterface {
   WindowImpl();
   virtual ~WindowImpl();
 
+  // Causes all generated windows classes to be unregistered at exit.
+  // This can cause result in errors for tests that don't destroy all instances
+  // of windows, but is necessary if the tests unload the classes WndProc.
+  static void UnregisterClassesAtExit();
+
   // Initializes the Window with a parent and an initial desired size.
   void Init(HWND parent, const gfx::Rect& bounds);