Fix more compiler warnings from deprecated application attributes

Also cleanup documentation, with the exception of the "High-DPI
Support in Qt Quick Controls" page, which needs to be either
removed or rewritten after some fact checking.

Change-Id: I3cdf1f8554f8f26627a9a5f17c2ee0038c933468
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

examples/quickcontrols2/flatstyle/main.cpp

@@ -53,7 +53,6 @@
 
 int main(int argc, char *argv[])
 {
-    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QApplication app(argc, argv);
 
     QQmlApplicationEngine engine;

examples/quickcontrols2/imagine/automotive/automotive.cpp

@@ -59,8 +59,6 @@ int main(int argc, char *argv[])
 {
     QGuiApplication::setApplicationName("Automotive");
     QGuiApplication::setOrganizationName("QtProject");
-    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
-    QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
 
     QGuiApplication app(argc, argv);
 

examples/quickcontrols2/imagine/musicplayer/musicplayer.cpp

@@ -57,8 +57,6 @@ int main(int argc, char *argv[])
 {
     QGuiApplication::setApplicationName("Music Player");
     QGuiApplication::setOrganizationName("QtProject");
-    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
-    QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
 
     QGuiApplication app(argc, argv);
 

examples/quickcontrols2/texteditor/texteditor.cpp

@@ -66,7 +66,6 @@ int main(int argc, char *argv[])
 {
     QGuiApplication::setApplicationName("Text Editor");
     QGuiApplication::setOrganizationName("QtProject");
-    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
 
 #ifdef QT_WIDGETS_LIB
     QApplication app(argc, argv);

examples/quickcontrols2/wearable/wearable.cpp

@@ -55,7 +55,6 @@
 
 int main(int argc, char *argv[])
 {
-    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QCoreApplication::setApplicationName("Wearable");
     QCoreApplication::setOrganizationName("QtProject");
 

src/imports/controls/doc/src/qtquickcontrols2-customize.qdoc

@@ -400,7 +400,6 @@
 
     int main(int argc, char *argv[])
     {
-        QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
         QGuiApplication app(argc, argv);
 
         qmlRegisterUncreatableType<MyStyle>("MyStyle", 1, 0, "MyStyle", "MyStyle is an attached property");

src/imports/controls/doc/src/qtquickcontrols2-gettingstarted.qdoc

@@ -67,7 +67,6 @@
 
     int main(int argc, char *argv[])
     {
-        QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
         QGuiApplication app(argc, argv);
         QQmlApplicationEngine engine;
         engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

src/imports/platform/doc/src/includes/widgets.qdocinc

@@ -19,7 +19,6 @@ Create an instance of \l QApplication in \c main():
 
 int main(int argc, char *argv[])
 {
-    QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QApplication app(argc, argv);
     QQmlApplicationEngine engine;
     engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

src/quickcontrols2/qquickstyle.cpp

@@ -76,7 +76,6 @@ Q_LOGGING_CATEGORY(lcQtQuickControlsStyle, "qt.quick.controls.style")
 
     int main(int argc, char *argv[])
     {
-        QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
         QGuiApplication app(argc, argv);
 
         QQuickStyle::setStyle("Material");

tests/auto/qquickiconimage/tst_qquickiconimage.cpp

@@ -561,7 +561,6 @@ void tst_qquickiconimage::translucentColors()
 
 int main(int argc, char *argv[])
 {
-    QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
     QGuiApplication app(argc, argv);
     Q_UNUSED(app);
     tst_qquickiconimage test;

tests/manual/buttons/buttons.cpp

@@ -52,7 +52,6 @@
 
 int main(int argc, char *argv[])
 {
-    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QGuiApplication app(argc, argv);
 
     QQmlApplicationEngine engine;

tests/manual/dialogs/dialogs.cpp

@@ -53,7 +53,6 @@
 
 int main(int argc, char *argv[])
 {
-    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QGuiApplication app(argc, argv);
 
     QQmlApplicationEngine engine;

tests/manual/headerview/main.cpp

@@ -204,7 +204,6 @@ private:
 
 int main(int argc, char *argv[])
 {
-    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QGuiApplication app(argc, argv);
 
     qmlRegisterType<TestTableModel>("TestTableModel", 0, 1, "TestTableModel");

tests/manual/nativestyle/main.cpp

@@ -40,7 +40,6 @@
 
 int main(int argc, char *argv[])
 {
-    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QGuiApplication app(argc, argv);
 
     // Todo: rename the "default" style to e.g "simple"

tests/manual/testbench/main.cpp

@@ -65,7 +65,6 @@ int main(int argc, char *argv[])
 {
     QGuiApplication::setApplicationName("testbench");
     QGuiApplication::setOrganizationName("QtProject");
-    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
 
     QGuiApplication app(argc, argv);