Bug: scroll behavior is ignored when opening a link for the first time

[gaearon]

Set scrollBehavior = browser or scrollToTop.

Open page A.
Scroll down.
Click on link to page B.

Expected: window is scrolled to top.
Actual: scroll position has not changed, as if scrollBehavior was none.

The reason for this is this check in ScrollContext:

    if (behavior && position)
      behavior.updateScrollPosition(position, actionType);
  }

It is wrong because even if we don't have a stored position, we must still let behavior handle it.
Behavior might not care about stored position at all — e.g. it might want to just scroll up.

[ryanflorence]

yeah, just send position = null?

[gaearon]

Yeah that's how I'd do it. Behavior might want to know if it's stored or unknown so it's better to send null then {x: 0, y: 0} I suppose.

[mjackson]

Seems like an easy fix. Let's do it.