perf(camerasource): Passed parameter by reference

src/video/camerasource.cpp

@@ -65,12 +65,12 @@ void CameraSource::open()
     open(CameraDevice::getDefaultDeviceName());
 }
 
-void CameraSource::open(const QString deviceName)
+void CameraSource::open(const QString& deviceName)
 {
     open(deviceName, VideoMode{0,0,0,0});
 }
 
-void CameraSource::open(const QString DeviceName, VideoMode Mode)
+void CameraSource::open(const QString& DeviceName, VideoMode Mode)
 {
     streamBlocker = true;
     QMutexLocker l{&biglock};

src/video/camerasource.h

@@ -52,8 +52,8 @@ public:
     /// Opens the source for the camera device in argument, in the settings, or the system default
     /// If a device is already open, the source will seamlessly switch to the new device
     void open();
-    void open(const QString deviceName);
-    void open(const QString deviceName, VideoMode mode);
+    void open(const QString& deviceName);
+    void open(const QString& deviceName, VideoMode mode);
     void close(); ///< Equivalent to opening the source with the video device "none". Stops streaming.
     bool isOpen();