Make QCoreApplication::startingUp() return false when appropriate.

Currently, QCoreApplication::startingUp() returns true even after
a QCoreApplication has been constructed. This patch makes it return
false after it has been constructed and adds checks to QApplication
and QGuiApplication to ensure that it returns true within the
constructor of these classes.

Task-number: QTBUG-2591
Change-Id: Ie511522d35b5658c20be43dd112eae18c205277f
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>

src/corelib/kernel/qcoreapplication.cpp

@@ -638,6 +638,8 @@ void QCoreApplication::init()
     d->processCommandLineArguments();
 
     qt_startup_hook();
+
+    QCoreApplicationPrivate::is_app_running = true; // No longer starting up.
 }
 
 /*!

src/gui/kernel/qguiapplication.cpp

@@ -926,6 +926,8 @@ static bool runningUnderDebugger()
 
 void QGuiApplicationPrivate::init()
 {
+    QCoreApplicationPrivate::is_app_running = false; // Starting up.
+
     bool doGrabUnderDebugger = false;
     QList<QByteArray> pluginList;
     // Get command line params

src/widgets/kernel/qapplication.cpp

@@ -588,6 +588,8 @@ extern void qRegisterWidgetsVariant();
 */
 void QApplicationPrivate::initialize()
 {
+    is_app_running = false; // Starting up.
+
     QWidgetPrivate::mapper = new QWidgetMapper;
     QWidgetPrivate::allWidgets = new QWidgetSet;
 
@@ -601,8 +603,6 @@ void QApplicationPrivate::initialize()
     qRegisterGuiStateMachine();
 #endif
 
-    is_app_running = true; // no longer starting up
-
     Q_Q(QApplication);
 
     if (qgetenv("QT_USE_NATIVE_WINDOWS").toInt() > 0)
@@ -629,6 +629,8 @@ void QApplicationPrivate::initialize()
     if (QApplication::desktopSettingsAware())
         if (const QPlatformTheme *theme = QGuiApplicationPrivate::platformTheme())
             QApplicationPrivate::enabledAnimations = theme->themeHint(QPlatformTheme::UiEffects).toInt();
+
+    is_app_running = true; // no longer starting up
 }
 
 /*****************************************************************************