Before saying how to develope it, mention what it's all about.
The text was shamelessly stolen from OpenHUB LibreOffice project
site: [1].

* [1] https://www.openhub.net/p/libreoffice

Change-Id: I9e018e441c4d3f176d1d21eddb7a65429a9f9fd2
Reviewed-on: https://gerrit.libreoffice.org/20252Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: jan iversen <jani@documentfoundation.org>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

Related: fdo#63211 for saving. This one adds the import side, plus
fallbacks to use the new FillStyle attributes in HTML im/export in a
SvxBrushItem. Also added graphic import for inline graphics. Comment
markers inserted at places where functionality may be added in the
future when the new FillStyle attributes would be more used in this
content. Unit test checks PageBackground and ParagraphBaground import.

Change-Id: I3f198677db553ad198e0add3162603a4735398f1
Reviewed-on: https://gerrit.libreoffice.org/20129Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

Change-Id: Id0a0aa66ffd5788873fa5dc99fcc1b912c0e90fa

Change-Id: I0067f2b2493f5ecd7430bbcbb3743407199d2a7e
Reviewed-on: https://gerrit.libreoffice.org/20247Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
Tested-by: Julien Nabet <serval2412@yahoo.fr>

"defaultbootstrap.o : error LNK2001: unresolved external symbol
'[thunk]:private: virtual class com::sun::star::uno::Sequence<class
rtl::OUString> __cdecl cppuhelper::ServiceManager::getAvailableServiceNames`adjustor{24}'
(void)'
(?getAvailableServiceNames@ServiceManager@cppuhelper@@GBI@EAA?AV?$Sequence@VOUString@rtl@@@uno@star@sun@com@@XZ)"

Change-Id: I04b7353305ffeeb316d70ab8408aeb52ea0f7186

Change-Id: Id30e7afb3024d94cacf392bcd72c952d5a2ba5c4

Change-Id: Id127668e6786665b819b7c0b1c0cd424ebff96bf

Change-Id: I14c2dc0be12151b5d4ea2ba3b65030f6f4494905

"thumbviewer.cxx(168,9) :  error: delete called on 'StreamOnZipBuffer' that has
virtual functions but non-virtual destructor"

Change-Id: I34510d54b9a99d8f1f9e8da0236625023c3fd94c

Change-Id: I2f170c8ad2ef30f49062fdeee4bcdcf5baf552db

...since ce59f885 "INTEGRATION: CWS
desktintgr03: #i34294#" commented out the uses (whicht got later removed
completely with 45f0cc2e "Remove commented code
in libs-core/shell")

Change-Id: Icb7f97b72634d07045f5880af33b372be36e66b2

Change-Id: Icb5476f117ec44f5a4dc3026595305293b99fdd8

Change-Id: I205861dd46d635b4b7be87ec8eb84cb70d8bf4d7

Change-Id: Ie16ca73ac3d622d00583ef454780f9a01b32d436

...which does not behave as expected with the given command line arguments, so
just strip "-cl.exe" (and any hard-coded command line arguments following it in
$CC, but that's probably rather harmless here).  Expects that clang-cl is given
with an ".exe" extension in $CC (not assuming that and stripping "-cl" and
everything that might follow could be a bit too agressive).

Change-Id: If99f964dda1369b7d4bbb63b3d634b93c9f935a8

Change-Id: I60589ff9a5b47bcc3c749238a9cd3d8e910b7ba5

Change-Id: I50aaeb264c901146c119192cbd961b20117788e1

Change-Id: I62fd53d6f39349405865783bc44edbb7929664a1

Change-Id: If88aae978bc7cabe212f645f8eedff14d36c062f

Change-Id: I1516acb038f08479cdd4ffd42d5af1e7ec555d10

Change-Id: I4331396f5bbc37306c09f0e9a1c6b2969922f66f

Change-Id: I0988cf701dea563e3990b4179879fbcd3778662d

Change-Id: Ie539b4f3e4295a8dcb1126371e5f2c75e9d723ab

Change-Id: Ib725e544d058c735e485db1586743746a5236488

...for size_t (i.e., unsigned long long on Windows 64-bit), chosing among the
int, unsigned int, long, unsigned long overloads.  MSVC apparently happily picks
one of them, but clang-cl rightly complains.

Change-Id: Ib245925bdf9e4a34add6ca435a95559f4f07c4d7

Change-Id: Id53c00a90f4f2d87e469ae4fe4121a5678dff5a4

Change-Id: I0a4256047ae0142a03903101036d2a3c8d17429b

Change-Id: I6103a8539c4d788fff1a7e3c3530a6ec7cd1f0c6

...apparently a copy of MSO_ShadeType removed with
e336d7f8 "Remove unused MSO_ShadeType" and
equally unused

Change-Id: If1660faa45c1445c302ac0c9a1a160674691c15d

...otherwise, as the class is SVX_DLLPUBLIC and---for better or worse---
SVX_DLLPUBLIC is shared between Library_svxcore and Library_svxcore, all .cxx in
Library_svx that happen to include cell.hxx would emit them (as well as those in
Library_svxcore, of course), and the copy ctor requires the vtable, which in
turn requires an adjustor thunk for Cell::getPropertyStates, which happens to
not be emitted into any of the Library_svx .cxx that require it under clang-cl
due to <https://llvm.org/bugs/show_bug.cgi?id=25641> "clang-cl: vtordisp thunks
not emitted for functions with class template specializations in their
signatures."

Change-Id: Ib03b7002f9dfe3c2df742640ef7406cf24a7cecd

...otherwise, as the class is SVX_DLLPUBLIC and---for better or worse---
SVX_DLLPUBLIC is shared between Library_svxcore and Library_svx, all .cxx in
Library_svxcore that happen to include svx/pageitem.hxx would emit it (as well
as those in Library_svx, of course).  But at least clang-cl at /O0 would want
to put SvxPageItem's (base-class) vtable in place in the dtor, so would also
emit the vtable, so would depend on SvxPageItem::operator==, but that is defined
in pageitem.cxx in Library_svx, against which Library_svxcore doesn't link.

Change-Id: Ibfc393c1de3e0bd6621c057d88b1b0f272820154

Change-Id: I539326ee46615adfd648acb15cbd3eacfd914989

Change-Id: Ie8cfbb51b706e3b2c1d0b33aef5156438e9c7134

Change-Id: I40a88271b32d81f5857dd41b237e2c486c7059a0

...for C-style cast from 'connectivity::ado::OLEString' to 'rtl::OUString', as
connectivity::ado::OLEString has conversion operators to both OUString and BSTR
(i.e., wchar_t*), so both the OUString copy ctor and
OUString(sal_Unicode const*) ctor match.  At least MSVC 2013 happily compiles
that without complaining, but clang-cl does.

Change-Id: Ica634cf19c0fcf1dbff377cb503f6ea6c8257898

Change-Id: I607bd38a8cbed1f6b140a1adeb198cf3334a9c5e

Change-Id: I49fd2093d619743d0d5aaaa4784bd5ef5bb330c6

Change-Id: Id332cdff634be042e026faf7cc75d8eaeb44a13e

Change-Id: Ic238339b521dbff2d7fbe899127ac7954036300f

Change-Id: Ie14d3b3474b7886add80bd6e223e76fbf964144e