tabbar: use unique_ptr for buttons, sizer & clean-up

Change-Id: I4c479f0581e5fde7c3c2c21dcb2a88a2039e09ba

include/svtools/tabbar.hxx

@@ -315,13 +315,9 @@ class SVT_DLLPUBLIC TabBar : public vcl::Window
     friend class    ImplTabSizer;
 
 private:
+    std::unique_ptr<TabBar_Impl> mpImpl;
+
     ImplTabBarList* mpItemList;
-    ImplTabButton*  mpFirstBtn;
-    ImplTabButton*  mpPrevBtn;
-    ImplTabButton*  mpNextBtn;
-    ImplTabButton*  mpLastBtn;
-    TabBar_Impl*    mpImpl;
-    TabBarEdit*     mpEdit;
     OUString        maEditText;
     Color           maSelColor;
     Color           maSelTextColor;
@@ -461,7 +457,7 @@ public:
     void            EndEditMode( bool bCancel = false );
     void            SetEditText( const OUString& rText ) { maEditText = rText; }
     const OUString& GetEditText() const { return maEditText; }
-    bool            IsInEditMode() const { return (mpEdit != NULL); }
+    bool            IsInEditMode() const;
     bool            IsEditModeCanceled() const { return mbEditCanceled; }
     sal_uInt16      GetEditPageId() const { return mnEditId; }