sw: save more vcl layout calls in SwFntObj

This builds on top of commit 436b829f5b904d76039db0818cff5dedf1ae89f1
(sw: save one vcl layout call in SwFntObj::DrawText(), 2018-08-16), but
now layouts are shared not only inside SwFntObj::DrawText(), but also
between SwFntObj::GetTextSize() and SwFntObj::DrawText().

To get there, create an SwFntObj cache member that stores already
calculated vcl layouts. SwFntObj already derives from SwCacheObj, so no
need to explicitly expire this cache member.

Total number of GenericSalLayout::LayoutText() invocations go down from
8 to 5 with this when pressing a key in Writer.

Change-Id: Ifbe84a5c00025604f9c1331b56074b3dc27864b5
Reviewed-on: https://gerrit.libreoffice.org/59879
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>

0 files changed, 0 insertions, 0 deletions