Remove unused former overriders

QImageIOPlugin::keys() was removed in Qt 5.0 by
c9d040c1f5b0ee0ddd37e924576ec3bbd990f2ed in qtbase.

Change-Id: Ifda96e4764aa82d6f608d9ee2e29bac554603705
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

src/plugins/imageformats/jp2/main.cpp

@@ -56,16 +56,10 @@ class QJp2Plugin : public QImageIOPlugin
     Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface" FILE "jp2.json")
 
 public:
-    QStringList keys() const;
     Capabilities capabilities(QIODevice *device, const QByteArray &format) const override;
     QImageIOHandler *create(QIODevice *device, const QByteArray &format = QByteArray()) const override;
 };
 
-QStringList QJp2Plugin::keys() const
-{
-    return QStringList() << QLatin1String("jp2") << QLatin1String("j2k");
-}
-
 QImageIOPlugin::Capabilities QJp2Plugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
     if (format == "jp2" || format == "j2k")

src/plugins/imageformats/macjp2/main.cpp

@@ -49,16 +49,10 @@ class QMacJp2Plugin : public QImageIOPlugin
     Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface" FILE "macjp2.json")
 
 public:
-    QStringList keys() const;
     Capabilities capabilities(QIODevice *device, const QByteArray &format) const override;
     QImageIOHandler *create(QIODevice *device, const QByteArray &format = QByteArray()) const override;
 };
 
-QStringList QMacJp2Plugin::keys() const
-{
-    return QStringList() << QStringLiteral("jp2");
-}
-
 QImageIOPlugin::Capabilities QMacJp2Plugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
     if (format == "jp2")

src/plugins/imageformats/mng/main.cpp

@@ -58,16 +58,10 @@ class QMngPlugin : public QImageIOPlugin
     Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface" FILE "mng.json")
 
 public:
-    QStringList keys() const;
     Capabilities capabilities(QIODevice *device, const QByteArray &format) const override;
     QImageIOHandler *create(QIODevice *device, const QByteArray &format = QByteArray()) const override;
 };
 
-QStringList QMngPlugin::keys() const
-{
-    return QStringList() << QLatin1String("mng");
-}
-
 QImageIOPlugin::Capabilities QMngPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
     if (format == "mng")

src/plugins/imageformats/tga/main.cpp

@@ -58,7 +58,6 @@ class QTgaPlugin : public QImageIOPlugin
 public:
     Capabilities capabilities(QIODevice * device, const QByteArray & format) const override;
     QImageIOHandler * create(QIODevice * device, const QByteArray & format = QByteArray()) const override;
-    QStringList keys() const;
 };
 
 QImageIOPlugin::Capabilities QTgaPlugin::capabilities(QIODevice *device, const QByteArray &format) const
@@ -84,11 +83,6 @@ QImageIOHandler* QTgaPlugin::create(QIODevice *device, const QByteArray &format)
     return tgaHandler;
 }
 
-QStringList QTgaPlugin::keys() const
-{
-    return QStringList() << QLatin1String("tga");
-}
-
 QT_END_NAMESPACE
 
 #include "main.moc"

src/plugins/imageformats/tiff/main.cpp

@@ -57,7 +57,6 @@ class QTiffPlugin : public QImageIOPlugin
 public:
     Capabilities capabilities(QIODevice * device, const QByteArray & format) const override;
     QImageIOHandler * create(QIODevice * device, const QByteArray & format = QByteArray()) const override;
-    QStringList keys() const;
 };
 
 QImageIOPlugin::Capabilities QTiffPlugin::capabilities(QIODevice *device, const QByteArray &format) const
@@ -85,11 +84,6 @@ QImageIOHandler* QTiffPlugin::create(QIODevice *device, const QByteArray &format
     return tiffHandler;
 }
 
-QStringList QTiffPlugin::keys() const
-{
-    return QStringList() << QLatin1String("tiff") << QLatin1String("tif");
-}
-
 QT_END_NAMESPACE
 
 #include "main.moc"

src/plugins/imageformats/wbmp/main.cpp

@@ -55,7 +55,6 @@ class QWbmpPlugin : public QImageIOPlugin
     Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface" FILE "wbmp.json")
 
 public:
-    QStringList keys() const;
     QImageIOPlugin::Capabilities capabilities(QIODevice *device, const QByteArray &format) const override;
     QImageIOHandler *create(QIODevice *device, const QByteArray &format = QByteArray()) const override;
 };
@@ -89,11 +88,6 @@ QImageIOHandler * QWbmpPlugin::create(QIODevice *device, const QByteArray &forma
     return handler;
 }
 
-QStringList QWbmpPlugin::keys() const
-{
-    return QStringList() << QLatin1String("wbmp");
-}
-
 QT_END_NAMESPACE
 
 #include "main.moc"