Fix layer cache memory leak

Fix layer cache memory leak

The issue was that, with caching disabled, the layer cache code was removing layers outside of a purge (i.e., in unlock) but not correctly cleaning up the GrPictureInfo objects (as is done in purgePlot).

Committed: https://skia.googlesource.com/skia/+/b32f0ad89119625feedb4f0403bbbc94fae44668

[robertphillips, 2014-11-04 14:31:31]

robertphillips@google.com changed reviewers:
+ egdaniel@google.com

[egdaniel, 2014-11-04 14:35:35]

lgtm

[robertphillips, 2014-11-04 14:37:09]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2014-11-04 14:37:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/703643002/1

[commit-bot: I haz the power, 2014-11-04 14:46:16]

Committed patchset #1 (id:1) as b32f0ad89119625feedb4f0403bbbc94fae44668