Roll src/third_party/skia c2d84bfa7421..8cae1e95a23b (4 commits) (flutter#12086)

https://skia.googlesource.com/skia.git/+log/c2d84bfa7421..8cae1e95a23b

git log c2d84bfa7421..8cae1e95a23b --date=short --no-merges --format='%ad %ae %s'
2019-09-09 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2019-09-09 herb@google.com Cleanup SkPackedGlyphID
2019-09-09 brianosman@google.com Remove temporary Metal pipeline cache size hack
2019-09-09 hcm@google.com Add release section for milestones and rel notes

Created with:
  gclient setdep -r src/third_party/skia@8cae1e95a23b

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC mtklein@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
TBR=mtklein@google.com

Author: skia-flutter-autoroll

DEPS

@@ -26,7 +26,7 @@ vars = {
   'skia_git': 'https://skia.googlesource.com',
   # OCMock is for testing only so there is no google clone
   'ocmock_git': 'https://github.com/erikdoe/ocmock.git',
-  'skia_revision': 'c2d84bfa74212bf97405429225b88944d1377c69',
+  'skia_revision': '8cae1e95a23b8781459efd6f56ef9fb724d28b81',
 
   # When updating the Dart revision, ensure that all entries that are
   # dependencies of Dart are also updated to match the entries in the

ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: 643ef2c6b141d64a158108082d17cfa7
+Signature: ed871eff3012bf417c06ce40822274ba
 
 UNUSED LICENSES: