Fix QProgressBar causing timer event spam

On Windows you will get a lot of timer events if you use QProgressBar
widget. This is because QWindowsStyle uses a timer to animate a
progress bar with unknown state (min and max values both zero). The
issue was fixed by starting the timer only if needed.

Task-number: QTBUG-10501
(cherry picked from commit  72e61b127470b044e370af7017fa8a5b0538244f)

Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

Change-Id: If9ff2ab99929d9b85a7ffa8f6fd47b045b982f67
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/widgets/styles/qwindowsstyle_p.h b/src/widgets/styles/qwindowsstyle_p.h
index b9f39a0940..1e517e9e79 100644
--- a/src/widgets/styles/qwindowsstyle_p.h
+++ b/src/widgets/styles/qwindowsstyle_p.h
@@ -71,13 +71,15 @@ class QWindowsStylePrivate : public QCommonStylePrivate
     Q_DECLARE_PUBLIC(QWindowsStyle)
 public:
     QWindowsStylePrivate();
+    void startAnimation(QObject *o, QProgressBar *bar);
+    void stopAnimation(QObject *o, QProgressBar *bar);
     bool hasSeenAlt(const QWidget *widget) const;
     bool altDown() const { return alt_down; }
     bool alt_down;
     QList<const QWidget *> seenAlt;
     int menuBarTimer;
 
-    QList<QProgressBar *> bars;
+    QList<QProgressBar *> animatedProgressBars;
     int animationFps;
     int animateTimer;
     QElapsedTimer startTime;