use const reference for OUString

Change-Id: I66b5f144da7951f36e32a840b8ed70f38539f105

include/oox/export/drawingml.hxx

@@ -136,11 +136,12 @@ public:
     void WriteGradientFill( ::com::sun::star::awt::Gradient rGradient );
     void WriteGrabBagGradientFill( ::com::sun::star::uno::Sequence< ::com::sun::star::beans::PropertyValue > aGradientStops, ::com::sun::star::awt::Gradient rGradient);
     void WriteBlipFill( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet > rXPropSet,
-                         OUString sBitmapURL, sal_Int32 nXmlNamespace,
+                         const OUString& sBitmapURL, sal_Int32 nXmlNamespace,
                          bool bWriteMode, bool bRelPathToMedia = false );
-    void WriteBlipFill( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet > rXPropSet, OUString sURLPropName );
     void WriteBlipFill( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet > rXPropSet,
-                         OUString sURLPropName, sal_Int32 nXmlNamespace );
+            const OUString& sURLPropName );
+    void WriteBlipFill( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet > rXPropSet,
+                         const OUString& sURLPropName, sal_Int32 nXmlNamespace );
     void WritePattFill( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet > rXPropSet );
     void WriteSrcRect( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet >, const OUString& );
     void WriteOutline( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet > rXPropSet );
@@ -148,7 +149,7 @@ public:
     void WriteLinespacing( ::com::sun::star::style::LineSpacing& rLineSpacing );
 
     OUString WriteBlip( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet > rXPropSet,
-                            OUString& rURL, bool bRelPathToMedia = false , const Graphic *pGraphic=NULL );
+            const OUString& rURL, bool bRelPathToMedia = false , const Graphic *pGraphic=NULL );
     void WriteBlipMode( ::com::sun::star::uno::Reference< ::com::sun::star::beans::XPropertySet > rXPropSet, const OUString& rURL );
 
     void WriteShapeTransformation( ::com::sun::star::uno::Reference< ::com::sun::star::drawing::XShape > rXShape,

oox/source/export/drawingml.cxx

@@ -804,7 +804,7 @@ OUString DrawingML::WriteImage( const Graphic& rGraphic , bool bRelPathToMedia )
     return sRelId;
 }
 
-OUString DrawingML::WriteBlip( Reference< XPropertySet > rXPropSet, OUString& rURL, bool bRelPathToMedia, const Graphic *pGraphic )
+OUString DrawingML::WriteBlip( Reference< XPropertySet > rXPropSet, const OUString& rURL, bool bRelPathToMedia, const Graphic *pGraphic )
 {
     OUString sRelId = pGraphic ? WriteImage( *pGraphic, bRelPathToMedia ) : WriteImage( rURL, bRelPathToMedia );
     sal_Int16 nBright = 0;
@@ -847,12 +847,12 @@ void DrawingML::WriteBlipMode( Reference< XPropertySet > rXPropSet, const OUStri
     }
 }
 
-void DrawingML::WriteBlipFill( Reference< XPropertySet > rXPropSet, OUString sURLPropName )
+void DrawingML::WriteBlipFill( Reference< XPropertySet > rXPropSet, const OUString& sURLPropName )
 {
     WriteBlipFill( rXPropSet, sURLPropName, XML_a );
 }
 
-void DrawingML::WriteBlipFill( Reference< XPropertySet > rXPropSet, OUString sURLPropName, sal_Int32 nXmlNamespace )
+void DrawingML::WriteBlipFill( Reference< XPropertySet > rXPropSet, const OUString& sURLPropName, sal_Int32 nXmlNamespace )
 {
     if ( GetProperty( rXPropSet, sURLPropName ) ) {
         OUString aURL;
@@ -864,7 +864,7 @@ void DrawingML::WriteBlipFill( Reference< XPropertySet > rXPropSet, OUString sUR
     }
 }
 
-void DrawingML::WriteBlipFill( Reference< XPropertySet > rXPropSet, OUString sBitmapURL, sal_Int32 nXmlNamespace, bool bWriteMode, bool bRelPathToMedia )
+void DrawingML::WriteBlipFill( Reference< XPropertySet > rXPropSet, const OUString& sBitmapURL, sal_Int32 nXmlNamespace, bool bWriteMode, bool bRelPathToMedia )
 {
     if ( !sBitmapURL.isEmpty() ) {
         DBG(fprintf (stderr, "URL: %s\n", OUStringToOString( sBitmapURL, RTL_TEXTENCODING_UTF8 ).getStr() ));