Create ImageDecoder target color space
This is towards allowing us to specify the transform that we want
applied to the image as it is decoded, as opposed to getting whatever
the global transform is.
This does not change any behavior.
BUG=
667420
Committed:
https://crrev.com/06f9ccab7e622c578258288e38554c05ec9a8dab
Cr-Commit-Position: refs/heads/master@{#433781}