fHeightForWidthLayoutContext
fHeightForWidthLayoutContext = context;
if (fHeightForWidthLayoutContext != NULL)
fHeightForWidthLayoutContext->AddListener(this);
fHeightForWidthLayoutContext = NULL;
BLayoutContext* fHeightForWidthLayoutContext;
if (context == fHeightForWidthLayoutContext)
if (fHeightForWidthLayoutContext != NULL) {
fHeightForWidthLayoutContext->RemoveListener(this);
fHeightForWidthLayoutContext = NULL;