Bug 559660. Mark Windows surfaces dirty when we muck with underlying bits. r=joe

If we don't do this some animated gifs break with the cairo update.

modules/libpr0n/src/imgFrame.cpp

@@ -853,6 +853,11 @@ nsresult imgFrame::LockImageData()
   if (mImageSurface)
     mImageSurface->Flush();
 
+#ifdef USE_WIN_SURFACE
+  if (mWinSurface)
+    mWinSurface->Flush();
+#endif
+
   return NS_OK;
 }
 
@@ -872,6 +877,11 @@ nsresult imgFrame::UnlockImageData()
   if (mImageSurface)
     mImageSurface->MarkDirty();
 
+#ifdef USE_WIN_SURFACE
+  if (mWinSurface)
+    mWinSurface->MarkDirty();
+#endif
+
 #ifdef XP_MACOSX
   // The quartz image surface (ab)uses the flush method to get the
   // cairo_image_surface data into a CGImage, so we have to call Flush() here.