Roll src/third_party/skia e6a2ad81ab40..8fec4140f614 (17 commits) (#14557)

https://skia.googlesource.com/skia.git/+log/e6a2ad81ab40..8fec4140f614

git log e6a2ad81ab40..8fec4140f614 --date=short --first-parent --format='%ad %ae %s'
2019-12-18 mtklein@google.com Reland "roll clang_win"
2019-12-18 mtklein@google.com demote -fsanitize=pointer-overflow to warning
2019-12-18 herb@google.com Only checksum and query a valid descriptor
2019-12-18 bsalomon@google.com "fix" formatting of auto generated cpp from fp
2019-12-18 kjlubick@google.com Properly free bytes in SkDescriptor fuzzer
2019-12-18 bsalomon@google.com Make sure random unit test processors use an alpha type compatible with texture data.
2019-12-18 mtklein@google.com disable warnings in ANGLE
2019-12-18 mtklein@google.com Revert "roll clang_win"
2019-12-18 robertphillips@google.com Change signature of several gpu backend methods
2019-12-18 mtklein@google.com roll clang_win
2019-12-18 kjlubick@google.com [canvaskit] Fix SaveLayer constants
2019-12-18 brianosman@google.com Runtime SkSL: Reflect inputs in SkRuntimeEffect
2019-12-18 bsalomon@google.com Reland x3 "Remove most of GrConfig.h"
2019-12-18 robertphillips@google.com Fix a sprinkling of GPU issues
2019-12-18 rmistry@google.com Make OUTPUT_DIRECTORY in ProdDoxyfile configurable
2019-12-18 csmartdalton@google.com Add a kWireframe flag to GrPipeline
2019-12-18 bsalomon@google.com Remove SkRuntimeEffect.h include from SkColorFilterPriv.h

Created with:
  gclient setdep -r src/third_party/skia@8fec4140f614

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 borenet@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: borenet@google.com

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': 'e6a2ad81ab407cf59f5038cc3ee1998925408c33',
+  'skia_revision': '8fec4140f614aae4316f386b852c60e1cfa04f00',
 
   # 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

-Signature: aa3b6f112eed8dcf37e5c7517d1efdde
+Signature: 9711a332eacc05c13292bd2d25e6839f
 
 UNUSED LICENSES: