ITS Beam background studies - first workflow (AliceO2Group#15268)

* ITS Beam background studies - first workflow

* fix clang

* fix CI error

* Fix statements in braces

* leftover...

* Fixing shift 1 bc

Author: nicolovalle

Detectors/ITSMFT/ITS/postprocessing/studies/CMakeLists.txt

@@ -15,6 +15,7 @@ SOURCES src/ImpactParameter.cxx
         src/PIDStudy.cxx
         src/ITSStudiesConfigParam.cxx
         src/AnomalyStudy.cxx
+	src/ITSBeamBackgroundStudy.cxx
         src/TrackCheck.cxx
         src/TrackExtension.cxx
         src/Efficiency.cxx

Detectors/ITSMFT/ITS/postprocessing/studies/include/ITSStudies/ITSBeamBackgroundStudy.h

@@ -0,0 +1,26 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+#ifndef O2_ITS_BEAMBKG_STUDY_H
+#define O2_ITS_BEAMBKG_STUDY_H
+
+#include "Framework/DataProcessorSpec.h"
+#include "ReconstructionDataFormats/GlobalTrackID.h"
+
+namespace o2::its::study
+{
+
+using mask_t = o2::dataformats::GlobalTrackID::mask_t;
+
+o2::framework::DataProcessorSpec getITSBeamBackgroundStudy(mask_t srcTracksMask, mask_t srcClustersMask, bool useMC);
+
+} // namespace o2::its::study
+#endif