Use a factory function to create GrPipeline and remove unused member

Use a factory function to create GrPipeline and remove unused member

Committed: https://skia.googlesource.com/skia/+/47dfc36e460356ef624ab90b82921ac6c8cc8e48

[bsalomon, 2015-08-10 15:14:19]

bsalomon@google.com changed reviewers:
+ egdaniel@google.com, joshualitt@google.com

[bsalomon, 2015-08-10 15:14:23]

The CQ bit was checked by bsalomon@google.com

[commit-bot: I haz the power, 2015-08-10 15:14:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1273803004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1273803004/1

[commit-bot: I haz the power, 2015-08-10 15:14:35]

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 2015-08-10 21:14 UTC

[egdaniel, 2015-08-10 15:18:42]

lgtm

[commit-bot: I haz the power, 2015-08-10 15:23:17]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/47dfc36e460356ef624ab90b82921ac6c8cc8e48