add new blit2 methods in support of antialiased hairlines guard flag SK_SUPPORT_LEGACY_BLITANTIH2V2

add new blit2 methods in support of antialiased hairlines

before:
   9M	1	528µs	530µs	539µs	607µs	5%	▁▁▁▁▁▁▁▁█▂	8888	path_hairline_small_AA_quad

after:
   9M	1	355µs	356µs	358µs	375µs	2%	▂▁▁▁▁▁▁▁▁█	8888	path_hairline_small_AA_quad

BUG=skia:

does require new baselines (bug chrome is guarded)

Committed: https://skia.googlesource.com/skia/+/dd83031b98db4c6d3d0de2353bf115152a7d1464

[reed1, 2015-04-14 19:38:11]

reed@google.com changed reviewers:
+ caryclark@google.com

[caryclark, 2015-04-14 19:50:34]

lgtm

[reed2, 2015-04-15 01:33:37]

The CQ bit was checked by reed@chromium.org

[reed2, 2015-04-15 01:33:37]

The patchset sent to the CQ was uploaded after l-g-t-m from caryclark@google.com
Link to the patchset: https://codereview.chromium.org/1060153003/#ps20001
(title: "specialize non-opaque color as well")

[commit-bot: I haz the power, 2015-04-15 01:33:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1060153003/20001

[commit-bot: I haz the power, 2015-04-15 01:40:00]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/dd83031b98db4c6d3d0de2353bf115152a7d1464

[jcgregorio, 2015-04-15 13:16:53]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/1085013003/ by jcgregorio@google.com.

The reason for reverting is: DEPS roll is failing, one such example:

http://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_rel...

More here:

   https://codereview.chromium.org/1091483003

This CL was the only CL in the roll when things started to fail..