Fix TabPage header to scroll to the top after header reparented

This is a bit better than it used to be but I still don't like
it. Having dedicated pages for history, tabs, and the new tab
could solve some issues that we are still having here like
activating search field triggers always scrolling and previous
content position is not restored.

As we a new design for toolbar and it affects to the tabs page, I think that we should not do too much workarounds over here instead we should start pushing new toolbar design forward.