debugger: remove unneded function

src/plugins/debugger/debuggerplugin.cpp

@@ -1057,8 +1057,7 @@ public slots:
     const CPlusPlus::Snapshot &cppCodeModelSnapshot() const;
 
     void showQtDumperLibraryWarning(const QString &details);
-    DebuggerMainWindow *debuggerMainWindow() const;
-    QWidget *mainWindow() const { return m_mainWindow; }
+    DebuggerMainWindow *mainWindow() const { return m_mainWindow; }
 
     bool isRegisterViewVisible() const;
     bool hasSnapshots() const { return m_snapshotHandler->size(); }
@@ -2585,11 +2584,6 @@ void DebuggerPluginPrivate::showMessage(const QString &msg, int channel, int tim
     }
 }
 
-DebuggerMainWindow *DebuggerPluginPrivate::debuggerMainWindow() const
-{
-    return qobject_cast<DebuggerMainWindow*>(mainWindow());
-}
-
 void DebuggerPluginPrivate::showQtDumperLibraryWarning(const QString &details)
 {
     QMessageBox dialog(mainWindow());