Bug 1316673 - Respect the scroll destination when doing asynchronous scrollIntoView. r=kats

MozReview-Commit-ID: 6sLjxUc9Df1

--HG--
extra : rebase_source : d884f2766379dfc3e2d4152f75c61b4bbc40fd72
extra : histedit_source : c374a841635442801c5403644c3db5c6bd164cb0

layout/base/nsPresShell.cpp

@@ -3563,7 +3563,7 @@ PresShell::ScrollFrameRectIntoView(nsIFrame*                aFrame,
       }
       ScrollToShowRect(sf, targetRect - sf->GetScrolledFrame()->GetPosition(),
                        aVertical, aHorizontal, aFlags);
-      nsPoint newPosition = sf->GetScrollPosition();
+      nsPoint newPosition = sf->LastScrollDestination();
       // If the scroll position increased, that means our content moved up,
       // so our rect's offset should decrease
       rect += oldPosition - newPosition;