Don't bother painting a selection into an empty rect. Avoid using an invalid surface for painting ops. b=380611 r+sr=vladimir

layout/base/nsPresShell.cpp

@@ -4891,7 +4891,7 @@ PresShell::PaintRangePaintInfo(nsTArray<nsAutoPtr<RangePaintInfo> >* aItems,
                                nsRect* aScreenRect)
 {
   nsPresContext* pc = GetPresContext();
-  if (!pc)
+  if (!pc || aArea.width == 0 || aArea.height == 0)
     return nsnull;
 
   nsIDeviceContext* deviceContext = pc->DeviceContext();
@@ -4940,8 +4940,10 @@ PresShell::PaintRangePaintInfo(nsTArray<nsAutoPtr<RangePaintInfo> >* aItems,
   gfxImageSurface* surface =
     new gfxImageSurface(gfxIntSize(pixelArea.width, pixelArea.height),
                         gfxImageSurface::ImageFormatARGB32);
-  if (!surface)
+  if (!surface || surface->CairoStatus()) {
+    delete surface;
     return nsnull;
+  }
 
   // clear the image
   gfxContext context(surface);
@@ -5066,6 +5068,8 @@ PresShell::RenderSelection(nsISelection* aSelection,
   // to allocate a surface area
   PRInt32 numRanges;
   aSelection->GetRangeCount(&numRanges);
+  NS_ASSERTION(numRanges > 0, "RenderSelection called with no selection");
+
   for (PRInt32 r = 0; r < numRanges; r++)
   {
     nsCOMPtr<nsIDOMRange> range;

widget/src/gtk2/nsImageToPixbuf.cpp

@@ -90,6 +90,11 @@ nsImageToPixbuf::ImageToPixbuf(nsIImage* aImage)
 GdkPixbuf*
 nsImageToPixbuf::SurfaceToPixbuf(gfxASurface* aSurface, PRInt32 aWidth, PRInt32 aHeight)
 {
+    if (aSurface->CairoStatus()) {
+        NS_ERROR("invalid surface");
+        return nsnull;
+    }
+
     nsRefPtr<gfxImageSurface> imgSurface;
     if (aSurface->GetType() == gfxASurface::SurfaceTypeImage) {
         imgSurface = NS_STATIC_CAST(gfxImageSurface*,