mozilla/pdf.js — pull request #4959 by nnethercote (2014-06-17 06:01:30+00:00)
Title: Zero the height and width of cached canvases before deleting them.

This is exactly the same idea as #4920, but for CachedCanvases.

This reduces peak RSS from ~1400 MiB to ~1100 MiB on my Mac when scrolling slowly through
the first 30 pages of a scanned black and white document.