loplugin:useuniqueptr in SdrPage

Change-Id: Ie3a471e67b7596c967a38b26c250f82f16b80e61
Reviewed-on: https://gerrit.libreoffice.org/53754Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

include/svx/svdpage.hxx

@@ -421,7 +421,7 @@ public:
 
 protected:
     // new MasterPageDescriptorVector
-    sdr::MasterPageDescriptor*                    mpMasterPageDescriptor;
+    std::unique_ptr<sdr::MasterPageDescriptor> mpMasterPageDescriptor;
 
     SdrLayerIDSet       aPrefVisiLayers;
     sal_uInt16          nPageNum;

svx/source/svdraw/svdpage.cxx

@@ -1413,7 +1413,7 @@ void SdrPage::TRG_SetMasterPage(SdrPage& rNew)
     if(mpMasterPageDescriptor)
         TRG_ClearMasterPage();
 
-    mpMasterPageDescriptor = new sdr::MasterPageDescriptor(*this, rNew);
+    mpMasterPageDescriptor.reset(new sdr::MasterPageDescriptor(*this, rNew));
     GetViewContact().ActionChanged();
 }
 
@@ -1426,8 +1426,7 @@ void SdrPage::TRG_ClearMasterPage()
         // the flushViewObjectContacts() will do needed invalidates by deleting the involved VOCs
         mpMasterPageDescriptor->GetUsedPage().GetViewContact().flushViewObjectContacts();
 
-        delete mpMasterPageDescriptor;
-        mpMasterPageDescriptor = nullptr;
+        mpMasterPageDescriptor.reset();
     }
 }