Don't try to render color fonts using distance fields

Don't try to render color fonts using distance fields.

Adds detection of ARGB mask format, which is only used for color fonts.

BUG=skia:2173
Committed: http://code.google.com/p/skia/source/detail?r=14098

[jvanverth1, 2014-04-07 19:56:03]

I'm keying off of the ARGB mask format to render color fonts when using bitmaps,
so it seems like this should work. But it's entirely possible/likely that I
missed something.

[bsalomon, 2014-04-07 20:32:46]

On 2014/04/07 19:56:03, JimVV wrote:
> I'm keying off of the ARGB mask format to render color fonts when using
bitmaps,
> so it seems like this should work. But it's entirely possible/likely that I
> missed something.

Assuming that the mask type is the right way to detect color bitmap fonts, lgtm.

[robertphillips, 2014-04-08 12:19:42]

some comment suggestions

https://codereview.chromium.org/224903012/diff/40001/src/gpu/GrDistanceFieldT...
File src/gpu/GrDistanceFieldTextContext.cpp (right):

https://codereview.chromium.org/224903012/diff/40001/src/gpu/GrDistanceFieldT...
src/gpu/GrDistanceFieldTextContext.cpp:61: 
// DF fonts can't predice what an arbitrary rasterizer or mask filer will do
// Stroking ... ?

https://codereview.chromium.org/224903012/diff/40001/src/gpu/GrDistanceFieldT...
src/gpu/GrDistanceFieldTextContext.cpp:73: 
// Use ARGB32 as a marker for color fonts which aren't supported by DFs ?

https://codereview.chromium.org/224903012/diff/40001/src/gpu/GrTextStrike.cpp
File src/gpu/GrTextStrike.cpp (right):

https://codereview.chromium.org/224903012/diff/40001/src/gpu/GrTextStrike.cpp...
src/gpu/GrTextStrike.cpp:334: } else {
// DF fonts currently do not support color emoji ?

[jvanverth1, 2014-04-08 19:49:14]

The CQ bit was checked by jvanverth@google.com

[commit-bot: I haz the power, 2014-04-08 19:49:22]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/jvanverth@google.com/224903012/60001

[commit-bot: I haz the power, 2014-04-08 20:14:49]

Change committed as 14098