If the image already had pre-multiplied alpha, the decoder would
pre-multiply those already pre-multiplied values again when decoding
the alpha plane separately from the main plane.
Prevent fully transparent areas from being black (or whatever the color
values there are) when rendering JXR images with planar alpha before all
data is available.
Can be enabled/disabled at runtime by toggling the 'media.jxr.enabled'
pref (disabled by default).
Two additional prefs are provided for testing purposes:
'media.jxr.autoaccept', and 'media.jxr.advertised_mime_type'
See comments in all.js for information on what these do.
This commit includes the MS OpenTech implementation of the decoder on
the browser side with some fixes applied; see the development in Pale
Moon GitGub issue #105 or my comments in the source code for more
information.
rhinoduck