To reproduce
1. Apply a bunch of in-flight patches (this is just a work log for me, sorry for the incomplete repro steps)
2. Make sure that the output space has a non-srgb transfer fn
3. Do a release build
4. Notice the following failures

native control button is black:
  images/12-55.html
  images/182.html
  images/2-dht.html
  images/23-55.html
  images/55.html

images are black:
  images/jpeg-yuv-progressive-canvas.html
  images/optimize-contrast-canvas.html
  images/paint-subrect-grid.html
  images/paint-subrect.html
  images/pixelated-canvas.html

Of note is that this does not happen if the output color space is not sRGB, and also does not happen in debug build (gulp).

Hoping all of these have the same root cause and are easy enough to fix.