sd: de-duplicate slide masters on save to pptx

pptx files have layouts separated from masters, so multiple layouts can
reference the same master. On import that master is duplicated for each
layout. So we want that if it is saved without modification, the created
file contains the same number of masters and layouts as the original
pptx file.

The commit d590f094ccd28ca449eff91692c2178058d5c621 "tdf#155512: sd:
filter: eppt: add "SlideLayout" property to Slide Master" tried to do
this but saved too many layouts, which appeared as extra masters on
reload. The commit bff76421e234df7246a7f49c71a11432f86e09d1 "tdf#157740
FILESAVE PPTX: fix explosion of the number of master slides" fixed the
issue of extra layouts but removed the de-duplication of masters.

This commit avoids saving duplicated masters while keeping the correct
saving of layouts.

testTdf157740_slideMasters now checks for the correct number of masters
and layouts.

Change-Id: I199c55abe59d39c64e1e3e1fbd620e88f4f7290d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178669
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
(cherry picked from commit 2d9c808d1952c18daa007b41e70fc7e63f6c5712)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/180539
Tested-by: Jenkins
Reviewed-by: Jaume Pujantell <jaume.pujantell@collabora.com>

0 files changed, 0 insertions, 0 deletions