[PATCH v2] user32: Make sure that passed window handle is scroll control before accessing wExtra in SCROLL_GetInternalInfo.

[Jacek Caban]

Fixes memory corruption in Office 2016.

Signed-off-by: Jacek Caban <jacek(a)codeweavers.com>
---
 dlls/user32/scroll.c       |  3 ++-
 dlls/user32/tests/scroll.c | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)