QStyle: return 'Fusion' instead of 'fusion'

This change should have no impact on Widgets, since style names
there are case-insensitive. But for QtQuick controls the style
names are case sensitive. So in order to use the style hint
from the platform theme for controls, we need to return
the name with an uppercase "F".

Change-Id: I360f43f174938202b0ef2cdfcde6daf39c9f39bb
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

src/gui/platform/unix/qgenericunixthemes.cpp

@@ -309,7 +309,7 @@ void QKdeThemePrivate::refresh()
     styleNames.clear();
     if (kdeVersion >= 5)
         styleNames << QStringLiteral("breeze");
-    styleNames << QStringLiteral("Oxygen") << QStringLiteral("fusion") << QStringLiteral("windows");
+    styleNames << QStringLiteral("Oxygen") << QStringLiteral("Fusion") << QStringLiteral("windows");
     if (kdeVersion >= 5)
         iconFallbackThemeName = iconThemeName = QStringLiteral("breeze");
     else
@@ -746,7 +746,7 @@ QVariant QGnomeTheme::themeHint(QPlatformTheme::ThemeHint hint) const
         return QVariant::fromValue(availableXdgFileIconSizes());
     case QPlatformTheme::StyleNames: {
         QStringList styleNames;
-        styleNames << QStringLiteral("fusion") << QStringLiteral("windows");
+        styleNames << QStringLiteral("Fusion") << QStringLiteral("windows");
         return QVariant(styleNames);
     }
     case QPlatformTheme::KeyboardScheme:

src/plugins/platforms/android/qandroidplatformtheme.cpp

@@ -464,7 +464,7 @@ QVariant QAndroidPlatformTheme::themeHint(ThemeHint hint) const
                 && m_androidStyleData) {
             return QStringList(QLatin1String("android"));
         }
-        return QStringList(QLatin1String("fusion"));
+        return QStringList(QLatin1String("Fusion"));
     case DialogButtonBoxLayout:
         return QVariant(QPlatformDialogHelper::AndroidLayout);
     case MouseDoubleClickDistance:

src/plugins/platforms/ios/qiostheme.mm

@@ -160,7 +160,7 @@ QVariant QIOSTheme::themeHint(ThemeHint hint) const
 {
     switch (hint) {
     case QPlatformTheme::StyleNames:
-        return QStringList(QStringLiteral("fusion"));
+        return QStringList(QStringLiteral("Fusion"));
     case KeyboardScheme:
         return QVariant(int(MacKeyboardScheme));
     default:

src/plugins/platforms/offscreen/qoffscreenintegration.cpp

@@ -173,7 +173,7 @@ public:
     {
         switch (h) {
         case StyleNames:
-            return QVariant(QStringList(QStringLiteral("fusion")));
+            return QVariant(QStringList(QStringLiteral("Fusion")));
         default:
             break;
         }

src/plugins/platforms/wasm/qwasmtheme.cpp

@@ -50,7 +50,7 @@ QWasmTheme::~QWasmTheme()
 QVariant QWasmTheme::themeHint(ThemeHint hint) const
 {
     if (hint == QPlatformTheme::StyleNames)
-        return QVariant(QStringList() << QLatin1String("fusion"));
+        return QVariant(QStringList() << QLatin1String("Fusion"));
     return QPlatformTheme::themeHint(hint);
 }