specialize setConcat for scale+translate

specialize setConcat for scale+translate, helps drawText perf

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/e8db3ef2a2161084fa8eb1fd1d54c35bfff52d6c

[reed1, 2014-09-30 14:02:12]

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

[reed1, 2014-09-30 14:02:23]

ptal

[reed1, 2014-09-30 14:02:26]

The CQ bit was checked by reed@google.com

[commit-bot: I haz the power, 2014-09-30 14:03:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/620433002/1

[commit-bot: I haz the power, 2014-09-30 14:03:27]

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 a valid reviewer till 2014-09-30 20:03 UTC

[jvanverth1, 2014-09-30 14:09:52]

lgtm

[commit-bot: I haz the power, 2014-09-30 14:24:50]

Committed patchset #1 (id:1) as e8db3ef2a2161084fa8eb1fd1d54c35bfff52d6c

[robertphillips, 2014-10-02 11:42:38]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/620973003/ by robertphillips@google.com.

The reason for reverting is: Experimental to see if this revert "fixes"
nanobench on the main console..