New QCameraInfo class.

The class allows to get the list of available cameras on the system as
well as getting some static information about them such as their unique
ID, display name, physical position and sensor orientation.

This makes QCamera::availableDevices() and QCamera::deviceDescription()
obsolete.

This patch contains the API, documentation and auto-tests but not the
actual implementation by each backend (except for retrieving the default
camera device).

[ChangeLog][QtMultimedia] Added new QCameraInfo class
[ChangeLog][QtMultimedia] QCamera: availableDevices() and
deviceDescription() are deprecated, use QCameraInfo instead

Change-Id: I64fd65729ab26a789468979ed5444ee90bb82cd0
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

src/plugins/wmf/wmfserviceplugin.cpp

@@ -105,6 +105,11 @@ QMediaServiceProviderHint::Features WMFServicePlugin::supportedFeatures(
         return QMediaServiceProviderHint::Features();
 }
 
+QByteArray WMFServicePlugin::defaultDevice(const QByteArray &) const
+{
+    return QByteArray();
+}
+
 QList<QByteArray> WMFServicePlugin::devices(const QByteArray &) const
 {
     return QList<QByteArray>();

src/plugins/wmf/wmfserviceplugin.h

@@ -49,10 +49,12 @@ QT_USE_NAMESPACE
 class WMFServicePlugin
     : public QMediaServiceProviderPlugin
     , public QMediaServiceSupportedDevicesInterface
+    , public QMediaServiceDefaultDeviceInterface
     , public QMediaServiceFeaturesInterface
 {
     Q_OBJECT
     Q_INTERFACES(QMediaServiceSupportedDevicesInterface)
+    Q_INTERFACES(QMediaServiceDefaultDeviceInterface)
     Q_INTERFACES(QMediaServiceFeaturesInterface)
     Q_PLUGIN_METADATA(IID "org.qt-project.qt.mediaserviceproviderfactory/5.0" FILE "wmf.json")
 public:
@@ -61,6 +63,7 @@ public:
 
     QMediaServiceProviderHint::Features supportedFeatures(const QByteArray &service) const;
 
+    QByteArray defaultDevice(const QByteArray &service) const;
     QList<QByteArray> devices(const QByteArray &service) const;
     QString deviceDescription(const QByteArray &service, const QByteArray &device);
 };