forgotten ComputeScanlineSize() (tdf#140917)

Change-Id: Id139cea52832b7973dfac47d309d5bba8299b4e1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/112263
Reviewed-by: Mark Hung <marklh9@gmail.com>
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>
Tested-by: Jenkins
(cherry picked from commit 7ba7a1170a46ad340d06822a03f7196ccef29d84)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/112227
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
diff --git a/vcl/skia/salbmp.cxx b/vcl/skia/salbmp.cxx
index eeb5282..e29f84b 100644
--- a/vcl/skia/salbmp.cxx
+++ b/vcl/skia/salbmp.cxx
@@ -320,6 +320,7 @@
    if (mEraseColorSet)
    { // Simple.
        mSize = mPixelsSize = newSize;
        ComputeScanlineSize();
        EraseInternal(mEraseColor);
        return true;
    }