add compose-colorfilter

add compose-colorfilter

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/b675a73c1f3f4a433c4893199a0bd11126dfe130

[reed2, 2015-03-01 22:45:32]

reed@chromium.org changed reviewers:
+ bsalomon@google.com, fmalita@chromium.org, reed@google.com

[reed2, 2015-03-01 22:45:36]

The CQ bit was checked by reed@chromium.org

[commit-bot: I haz the power, 2015-03-01 22:46:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/969673002/20001

[commit-bot: I haz the power, 2015-03-01 22:46:40]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-03-02 04:46 UTC

[reed2, 2015-03-02 00:21:19]

Brian, how should we approach GL for this?
- asCompose?
- compose the fragments?
- other?

[f(malita), 2015-03-02 00:46:51]

The CQ bit was unchecked by fmalita@chromium.org

[f(malita), 2015-03-02 00:47:07]

lgtm

https://codereview.chromium.org/969673002/diff/20001/include/core/SkColorFilt...
File include/core/SkColorFilter.h (right):

https://codereview.chromium.org/969673002/diff/20001/include/core/SkColorFilt...
include/core/SkColorFilter.h:130: static SkColorFilter*
CreateComposeFilter(SkColorFilter* outer, SkColorFilter* inner);
I was expecting the arg order to correspond to the order in which the filters
are applied, and found the current order slightly surprising. I presume it's due
to C' = outer(inner(C)), so from that angle it does make sense.

[reed2, 2015-03-02 01:44:43]

Either order can be made to make sense :)

I was looking at composeimagefilter and composepatheffect, both of which take
(outer, inner).

[reed2, 2015-03-02 01:59:22]

The CQ bit was checked by reed@chromium.org

[commit-bot: I haz the power, 2015-03-02 02:00:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/969673002/20001

[commit-bot: I haz the power, 2015-03-02 02:00:53]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/b675a73c1f3f4a433c4893199a0bd11126dfe130

[reed2, 2015-03-02 03:15:25]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/971653002/ by reed@chromium.org.

The reason for reverting is: need to register subclass for serialization.