loplugin:useuniqueptr in ScAccessiblePreviewCell

Change-Id: I99b9809b3924285b4f0d58905352777b948ee592
Reviewed-on: https://gerrit.libreoffice.org/56546
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

sc/source/ui/Accessibility/AccessiblePreviewCell.cxx

@@ -74,8 +74,7 @@ void SAL_CALL ScAccessiblePreviewCell::disposing()
         mpViewShell = nullptr;
     }
 
-    if (mpTextHelper)
-        DELETEZ(mpTextHelper);
+    mpTextHelper.reset();
 
     ScAccessibleCellBase::disposing();
 }
@@ -271,10 +270,10 @@ void ScAccessiblePreviewCell::CreateTextHelper()
 {
     if (!mpTextHelper)
     {
-        mpTextHelper = new ::accessibility::AccessibleTextHelper(
+        mpTextHelper.reset( new ::accessibility::AccessibleTextHelper(
             o3tl::make_unique<ScAccessibilityEditSource>(
                 o3tl::make_unique<ScAccessiblePreviewCellTextData>(
-                    mpViewShell, maCellAddress)));
+                    mpViewShell, maCellAddress))) );
         mpTextHelper->SetEventSource( this );
 
         // paragraphs in preview are transient

sc/source/ui/inc/AccessiblePreviewCell.hxx

@@ -85,7 +85,7 @@ protected:
 private:
     ScPreviewShell* mpViewShell;
 
-    accessibility::AccessibleTextHelper* mpTextHelper;
+    std::unique_ptr<accessibility::AccessibleTextHelper> mpTextHelper;
 
     bool IsDefunc(
         const css::uno::Reference<css::accessibility::XAccessibleStateSet>& rxParentStates);