Steps to reproduce: 1. Apply cairo 1.10 patch 2. Load http://www.flickriver.com/ 3. Set image.mem.min_discard_timeout_ms to 0 4. Scroll to the bottom so that all 500 images load. 5. Switch to a different tab like about:memory 6. Wait for the images to be discarded by watching about:memory 7. Switch back to the flickriver tab and scroll through the whole page 8. goto 5. Eventually we run out of addresses space. You can see it growing by using vmmap.exe

This was because of the d2d debug layer