Regarding comment https://github.com/sailfishos/sailfish-browser/pull/23#issuecomment-37937454 once tab count is zero current tab is invalid. So over here you could set tab.url = "", tab.title = "", tab.thumbnailPath = "". But please check that tabId is 0 (invalid), it'll write the data to the database but for the empty url.

Adding a guard for DeclarativeTab::updateTab @ 242 would prevent database write...

```
if (m_valid && (urlHasChanged || titleHasChanged)) {
...
}
```