sc a11y: Pass OAccessible for ScAccessibleCellBase parent

Switch param for the ScAccessibleCellBase ctor
from the abstract XAccessible UNO interface to the
more concrete OAccessible.

Change-Id: I967d9582a9b1f4b07364c1344b0fcbbcc43ea228
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/210661
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Tested-by: Jenkins

sc/source/ui/Accessibility/AccessibleCellBase.cxx

@@ -44,10 +44,10 @@ using namespace ::com::sun::star::accessibility;
 
 #define DEFAULT_LINE_WIDTH 2
 
-ScAccessibleCellBase::ScAccessibleCellBase(const uno::Reference<XAccessible>& rxParent,
+ScAccessibleCellBase::ScAccessibleCellBase(const rtl::Reference<comphelper::OAccessible>& rpParent,
                                            ScDocument* pDoc, const ScAddress& rCellAddress,
                                            sal_Int64 nIndex)
-    : ImplInheritanceHelper(rxParent, AccessibleRole::TABLE_CELL)
+    : ImplInheritanceHelper(rpParent, AccessibleRole::TABLE_CELL)
     , maCellAddress(rCellAddress)
     , mpDoc(pDoc)
     , mnIndex(nIndex)

sc/source/ui/inc/AccessibleCellBase.hxx

@@ -28,11 +28,9 @@ class ScAccessibleCellBase
                                          css::accessibility::XAccessibleValue>
 {
 public:
-    ScAccessibleCellBase(
-        const css::uno::Reference<css::accessibility::XAccessible>& rxParent,
-        ScDocument* pDoc,
-        const ScAddress& rCellAddress,
-        sal_Int64 nIndex);
+    ScAccessibleCellBase(const rtl::Reference<comphelper::OAccessible>& rpParent, ScDocument* pDoc,
+                         const ScAddress& rCellAddress, sal_Int64 nIndex);
+
 protected:
     virtual ~ScAccessibleCellBase() override;
 public: