tdf#115549 Check xPropset is exist.

Checks xPropset is exist for chart handling on LibreOffice Online.

Change-Id: I57947fd23e089ace4df011873613c2f886770b30
Reviewed-on: https://gerrit.libreoffice.org/68493Reviewed-by: Andras Timar <andras.timar@collabora.com>
Tested-by: Andras Timar <andras.timar@collabora.com>

filter/source/svg/svgexport.cxx

@@ -2025,6 +2025,8 @@ bool SVGFilter::implCreateObjects()
             // - tiled bitmap: an image element is exported for each tile,
             //   this is really too expensive!
             Reference< XPropertySet > xPropSet( xDrawPage, UNO_QUERY );
+            if( xPropSet.is() )
+            {
                 Reference< XPropertySet > xBackground;
                 xPropSet->getPropertyValue( "Background" ) >>= xBackground;
                 if( xBackground.is() )
@@ -2037,6 +2039,7 @@ bool SVGFilter::implCreateObjects()
                         implCreateObjectsFromBackground( xDrawPage );
                     }
                 }
+            }
             implCreateObjectsFromShapes( xDrawPage, xDrawPage );
         }
     }