Fixed tst_QGL::destroyFBOAfterContext().

Properly free QOpenGLContext in QGLContext::reset(), if we own it.

Change-Id: Ibd913283cf8b3b8a4dc6295a878a22a3989309a7
Reviewed-on: http://codereview.qt.nokia.com/4320
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Jørgen Lind <jorgen.lind@nokia.com>

src/opengl/qgl.cpp

@@ -1532,6 +1532,7 @@ void QGLContextPrivate::init(QPaintDevice *dev, const QGLFormat &format)
     q->setDevice(dev);
 
     guiGlContext = 0;
+    ownContext = false;
     fbo = 0;
     crWin = false;
     initDone = false;

src/opengl/qgl_p.h

@@ -299,6 +299,8 @@ public:
     void swapRegion(const QRegion &region);
 
     QOpenGLContext *guiGlContext;
+    bool ownContext;
+
     void setupSharing();
 
     QGLFormat glFormat;

src/opengl/qgl_qpa.cpp

@@ -148,7 +148,9 @@ bool QGLContext::chooseContext(const QGLContext* shareContext)
             widget->winId();//make window
         }
 
-        delete d->guiGlContext;
+        if (d->ownContext)
+            delete d->guiGlContext;
+        d->ownContext = true;
         QOpenGLContext *shareGlContext = shareContext ? shareContext->d_func()->guiGlContext : 0;
         d->guiGlContext = new QOpenGLContext;
         d->guiGlContext->setFormat(winFormat);
@@ -180,8 +182,13 @@ void QGLContext::reset()
     d->initDone = false;
     QGLContextGroup::removeShare(this);
     if (d->guiGlContext) {
-        d->guiGlContext->setQGLContextHandle(0,0);
+        if (d->ownContext)
+            delete d->guiGlContext;
+        else
+            d->guiGlContext->setQGLContextHandle(0,0);
+        d->guiGlContext = 0;
     }
+    d->ownContext = false;
 }
 
 void QGLContext::makeCurrent()
@@ -385,6 +392,7 @@ QGLContext::QGLContext(QOpenGLContext *context)
     d->init(0, QGLFormat::fromSurfaceFormat(context->format()));
     d->guiGlContext = context;
     d->guiGlContext->setQGLContextHandle(this,qDeleteQGLContext);
+    d->ownContext = false;
     d->valid = context->isValid();
     d->setupSharing();
 }