Resolves: fdo#71527 don't crash in presenter console

but we're now dropping slides in there for some reason so
this is just a don't crash band-aid and not the fix
for the deeper problem

Change-Id: I2f70471d03979ffb86b6289e7a432f4505c1b556

sd/source/ui/presenter/SlideRenderer.cxx

@@ -134,9 +134,15 @@ Reference<rendering::XBitmap> SlideRenderer::createPreviewForCanvas (
     cppcanvas::BitmapCanvasSharedPtr pCanvas (cppcanvas::VCLFactory::getInstance().createCanvas(
         Reference<rendering::XBitmapCanvas>(rxCanvas, UNO_QUERY)));
     if (pCanvas.get() != NULL)
-        return cppcanvas::VCLFactory::getInstance().createBitmap(
+    {
+        cppcanvas::BitmapSharedPtr xBitmap(
+            cppcanvas::VCLFactory::getInstance().createBitmap(
             pCanvas,
-            CreatePreview(rxSlide, rMaximalSize, nSuperSampleFactor))->getUNOBitmap();
+            CreatePreview(rxSlide, rMaximalSize, nSuperSampleFactor)));
+        if (xBitmap.get() == NULL)
+            return NULL;
+        return xBitmap->getUNOBitmap();
+    }
     else
         return NULL;
 }

sdext/source/presenter/PresenterPaneContainer.cxx

@@ -192,7 +192,8 @@ PresenterPaneContainer::SharedPaneDescriptor
         {
             pDescriptor->mxView = rxView;
             pDescriptor->mpViewBackground = rpViewBackground;
-            pDescriptor->mxPane->SetBackground(rpViewBackground);
+            if (pDescriptor->mxPane.is())
+                pDescriptor->mxPane->SetBackground(rpViewBackground);
             try
             {
                 if ( ! pDescriptor->maViewInitialization.empty())