Core: Pass const string by reference

Change-Id: Ic927334a04cf61bccede3179eee0ca679c5b998f
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/coreplugin/documentmanager.cpp

@@ -867,8 +867,8 @@ bool DocumentManager::saveModifiedDocument(IDocument *document, const QString &m
 */
 
 QStringList DocumentManager::getOpenFileNames(const QString &filters,
-                                          const QString pathIn,
-                                          QString *selectedFilter)
+                                              const QString &pathIn,
+                                              QString *selectedFilter)
 {
     QString path = pathIn;
     if (path.isEmpty()) {

src/plugins/coreplugin/documentmanager.h

@@ -90,8 +90,8 @@ public:
     static bool saveDocument(IDocument *document, const QString &fileName = QString(), bool *isReadOnly = 0);
 
     static QStringList getOpenFileNames(const QString &filters,
-                                 const QString path = QString(),
-                                 QString *selectedFilter = 0);
+                                        const QString &path = QString(),
+                                        QString *selectedFilter = 0);
     static QString getSaveFileName(const QString &title, const QString &pathIn,
                             const QString &filter = QString(), QString *selectedFilter = 0);
     static QString getSaveFileNameWithExtension(const QString &title, const QString &pathIn,