Add name() getter in QPlatformTheme

This patch adds a getter for the current platform theme's name.
It is populated by QPlatformThemeFactory::create() if a plugin has been
loaded successfully.

Change-Id: I2c891c46e7dfcc262c35e32e345ae3dc2623e3a5
Reviewed-by: Oliver Eftevaag <oliver.eftevaag@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/gui/kernel/qplatformtheme.cpp

@@ -850,6 +850,11 @@ unsigned QPlatformThemePrivate::currentKeyPlatforms()
     return result;
 }
 
+QString QPlatformTheme::name() const
+{
+    return d_func()->name;
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qplatformtheme.cpp"

src/gui/kernel/qplatformtheme.h

@@ -317,10 +317,14 @@ public:
     static QVariant defaultThemeHint(ThemeHint hint);
     static QString defaultStandardButtonText(int button);
     static QString removeMnemonics(const QString &original);
+    QString name() const;
 
 protected:
     explicit QPlatformTheme(QPlatformThemePrivate *priv);
     QScopedPointer<QPlatformThemePrivate> d_ptr;
+
+private:
+    friend class QPlatformThemeFactory;
 };
 
 QT_END_NAMESPACE

src/gui/kernel/qplatformtheme_p.h

@@ -41,6 +41,8 @@ public:
     static unsigned currentKeyPlatforms();
 
     QPalette *systemPalette;
+
+    QString name;
 };
 
 QT_END_NAMESPACE

src/gui/kernel/qplatformthemefactory.cpp

@@ -8,6 +8,8 @@
 #include "qmutex.h"
 
 #include "qguiapplication.h"
+#include "qplatformtheme.h"
+#include "qplatformtheme_p.h"
 #include "qdebug.h"
 
 QT_BEGIN_NAMESPACE
@@ -22,7 +24,10 @@ QPlatformTheme *QPlatformThemeFactory::create(const QString& key, const QString
     QStringList paramList = key.split(u':');
     const QString platform = paramList.takeFirst().toLower();
     loader->setExtraSearchPath(platformPluginPath);
-    return qLoadPlugin<QPlatformTheme, QPlatformThemePlugin>(loader(), platform, paramList);
+    QPlatformTheme *theme = qLoadPlugin<QPlatformTheme, QPlatformThemePlugin>(loader(), platform, paramList);
+    if (theme)
+        theme->d_func()->name = key;
+    return theme;
 }
 
 /*!