Added check against existing of a valid Stats object in ViewerBase::renderinTraverls() to prevent crash.

Added default View Stats into src/osgViewer/View.cpp to enable stats to be collected for views

src/osgViewer/View.cpp

@@ -148,6 +148,8 @@ View::View():
     getCamera()->setRenderer(createRenderer(getCamera()));
 
     setEventQueue(new osgGA::EventQueue);
+    
+    setStats(new osg::Stats("View"));
 }
 
 
@@ -163,6 +165,8 @@ View::View(const osgViewer::View& view, const osg::CopyOp& copyop):
     getCamera()->setRenderer(createRenderer(getCamera()));
 
     setEventQueue(new osgGA::EventQueue);
+
+    setStats(new osg::Stats("View"));
 }
 
 View::~View()

src/osgViewer/ViewerBase.cpp

@@ -653,7 +653,7 @@ void ViewerBase::renderingTraversals()
             View* view = *vitr;
             osg::Stats* stats = view->getStats();            
             osg::Node* sceneRoot = view->getSceneData();
-            if (sceneRoot)
+            if (sceneRoot && stats)
             {
                 osgUtil::StatsVisitor statsVisitor;
                 sceneRoot->accept(statsVisitor);