Hide/show widget on Windows screen lock/unlock

ui/views/win/hwnd_message_handler_delegate.h

Index: ui/views/win/hwnd_message_handler_delegate.h
diff --git a/ui/views/win/hwnd_message_handler_delegate.h b/ui/views/win/hwnd_message_handler_delegate.h
index 55ac4407197e71ba103f30f885150975acc33c45..6ac4024e2c2454650415cc237e399d191c1a748e 100644
--- a/ui/views/win/hwnd_message_handler_delegate.h
+++ b/ui/views/win/hwnd_message_handler_delegate.h
@@ -154,6 +154,12 @@ class VIEWS_EXPORT HWNDMessageHandlerDelegate {
   // Called when the window's visibility changed. |visible| holds the new state.
   virtual void HandleVisibilityChanged(bool visible) = 0;
 
+  // Called when the "calculated" window's visibility changed.
+  // OS doesn't mark windows hidden on screen lock or when other opaque windows
+  // cover them.
+  // |visible| holds the new state.
+  virtual void HandleSoftVisibilityChanged(bool visible) = 0;
+
   // Called when the window's client size changed. |new_size| holds the new
   // size.
   virtual void HandleClientSizeChanged(const gfx::Size& new_size) = 0;