Fix a missing titleChanged signal on navigation

WebContentsView::SetPageTitle is only called when the Blink page
updated its title. For navigations we have to listen for
NavigationStateChanged.

Also update the history test to check this case.

Change-Id: Ia89c61b32913d647a63b2fb9a4cdf3f6867c4f0c
Reviewed-by: Pierre Rossi <pierre.rossi@gmail.com>