Add ASTC to list of alpha compressed formats

Add ASTC to list of alpha compressed formats

Committed: https://skia.googlesource.com/skia/+/2a413df4dacaf00920d02ac1df290d789a48b64a

[robertphillips, 2014-07-24 14:37:51]

lgtm
How will this work in the shiny future where we also support RGB ASTC?

[bsalomon, 2014-07-24 15:00:27]

lgtm

[krajcevski, 2014-07-24 15:03:28]

The CQ bit was checked by krajcevski@google.com

[commit-bot: I haz the power, 2014-07-24 15:03:48]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/krajcevski@google.com/412113004/1

[krajcevski, 2014-07-24 15:12:30]

On 2014/07/24 14:37:51, robertphillips wrote:
> lgtm
> How will this work in the shiny future where we also support RGB ASTC?

I'm not totally sure why there's a distinction between alpha-only and RGB
textures at the config level. Whether or not they should be read as RGB or
alpha-only should probably come from their use case...? At least, that was the
argument in the texture swizzle extension which is what this function gets used
for.

[commit-bot: I haz the power, 2014-07-24 15:16:05]

Change committed as 2a413df4dacaf00920d02ac1df290d789a48b64a