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Chrome and Mozilla support color space information in a BMP image [1],
when the BMP has (at least) a 108-byte BITMAPV4HEADER header [2].

Change piex-wasm BMP generation code to use a BITMAPV4HEADER. When the
preview image is sRGB, write that to the BITMAPV4HEADER. Otherwise the
image is 'adobeRgb' color space: write the RGB CIEXYZ tristimulus (the
gamut) and gamma of the AdobeRGB1988 color space, in the encoded forms
required by the BITMAPV4HEADER definition.

With this change, all images returned by peix-wasm have embedded color
space information so rendering these images in a color managed browser
like Chrome produces color-correct rendering.

[1] https://mzl.la/36S5Fm3
[2] https://bit.ly/30Iag6l

Bug: 1132695
Change-Id: Ic53d53f0a68274bb3b4f13fd31c14991d276786b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2454891Reviewed-by: Alex Danilo <adanilo@chromium.org>
Commit-Queue: Alex Danilo <adanilo@chromium.org>
Auto-Submit: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814565}