Read :/qtquickcontrols2.conf in QQuickStylePlugin

QQuickTheme is going to be promoted from libQQC2 to libQQT2 so that it
can provide dark and light palettes (and later, icons). The first step
is to refactor out the :/qtquickcontrols2.conf reading code, which
cannot be in style-agnostic libQQT2. Read the conf file in QQuickStyle
Plugin instead. The additional benefit is that we don't need duplicate
name() methods for styles and their themes. Even though QQuickStyle
Plugin's name handling is case-insensitive, QSetting is case-sensitive.
Therefore all QQuickStylePlugin::name() overrides have been updated
to use capital first letter. This name is used to lookup the correct
section in :/qtquickcontrols2.conf.

Task-number: QTBUG-63331
Change-Id: I07b1269d9dbc2c9568e6f22f2da75951fde7b669
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

2 files changed, 3 insertions, 4 deletions

diff --git a/src/imports/controls/fusion/qquickfusiontheme.cpp b/src/imports/controls/fusion/qquickfusiontheme.cpp
index 31494efb..78465b6b 100644
--- a/src/imports/controls/fusion/qquickfusiontheme.cpp
+++ b/src/imports/controls/fusion/qquickfusiontheme.cpp
@@ -39,7 +39,6 @@
 QT_BEGIN_NAMESPACE
 
 QQuickFusionTheme::QQuickFusionTheme()
-    : QQuickTheme(QStringLiteral("Fusion"))
 {
 }
 
diff --git a/src/imports/controls/fusion/qtquickcontrols2fusionstyleplugin.cpp b/src/imports/controls/fusion/qtquickcontrols2fusionstyleplugin.cpp
index 9a329d03..2d1a6e28 100644
--- a/src/imports/controls/fusion/qtquickcontrols2fusionstyleplugin.cpp
+++ b/src/imports/controls/fusion/qtquickcontrols2fusionstyleplugin.cpp
@@ -72,7 +72,7 @@ public:
     void initializeEngine(QQmlEngine *engine, const char *uri) override;
 
     QString name() const override;
-    QQuickProxyTheme *createTheme() const override;
+    QQuickTheme *createTheme() const override;
 };
 
 QtQuickControls2FusionStylePlugin::QtQuickControls2FusionStylePlugin(QObject *parent) : QQuickStylePlugin(parent)
@@ -109,10 +109,10 @@ void QtQuickControls2FusionStylePlugin::initializeEngine(QQmlEngine *engine, con
 
 QString QtQuickControls2FusionStylePlugin::name() const
 {
-    return QStringLiteral("fusion");
+    return QStringLiteral("Fusion");
 }
 
-QQuickProxyTheme *QtQuickControls2FusionStylePlugin::createTheme() const
+QQuickTheme *QtQuickControls2FusionStylePlugin::createTheme() const
 {
     return new QQuickFusionTheme;
 }