This reference argument can be const

Change-Id: I4d8d23d34aa72a0101bc18e98983ea8840806462

sw/inc/ndgrf.hxx

@@ -95,7 +95,7 @@ class SW_DLLPUBLIC SwGrfNode: public SwNoTxtNode
         input parameter - reference to storage, which should contain the
         embedded graphic stream.
 
-        @param _aStrmName
+        @param rStrmName
         input parameter - proposed name of the embedded graphic stream.
 
         @return SvStream*
@@ -104,7 +104,7 @@ class SW_DLLPUBLIC SwGrfNode: public SwNoTxtNode
     */
     SvStream* _GetStreamForEmbedGrf(
             const ::com::sun::star::uno::Reference< ::com::sun::star::embed::XStorage >& _refPics,
-            String& _aStrmName ) const;
+            const String& rStrmName ) const;
 
     /** helper method to get a substorage of the document storage for readonly access.
 

sw/source/core/graphic/ndgrf.cxx

@@ -870,12 +870,13 @@ uno::Reference< embed::XStorage > SwGrfNode::_GetDocSubstorageOrRoot( const Stri
 */
 SvStream* SwGrfNode::_GetStreamForEmbedGrf(
             const uno::Reference< embed::XStorage >& _refPics,
-            String& _aStrmName ) const
+            const String& rStrmName ) const
 {
     SvStream* pStrm( 0L );
 
-    if( _refPics.is() && _aStrmName.Len() )
+    if( _refPics.is() && rStrmName.Len() )
     {
+        String _aStrmName(rStrmName);
         // If stream doesn't exist in the storage, try access the graphic file by
         // re-generating its name.
         // A save action can have changed the filename of the embedded graphic,