Fix http://b/issue?id=2400423.

When the same page is loaded, updateRestoreState
will be false when we finish the first layout. As
we are still in the same page, we don't want to
update the current zoom/scroll. But in some cases,
like a site switch from mobile to full site and
keeps the same url, we do want to update the zoom
range as the viewport spec changed. Otherwise, user
can't zoom in the full site as the WebView thought
it is still a mobile non-scalable page.