Roll src/third_party/skia 6808e2d1faac..c876404e64d2 (6 commits) (flutter/engine#10292)

https://skia.googlesource.com/skia.git/+log/6808e2d1faac..c876404e64d2

git log 6808e2d1faac..c876404e64d2 --date=short --no-merges --format='%ad %ae %s'
2019-07-31 halcanary@google.com tools/sk_app/macos: support command key
2019-07-31 benjaminwagner@google.com Set mac_sdk_min=10.13 for CommandBuffer builds
2019-07-31 halcanary@google.com SkPDF: SkPDFMakeShader handles pathological inputs better.
2019-07-31 bsalomon@google.com Remove GrCaps::SupportedRead::fSwizzle and supporting code
2019-07-31 robertphillips@google.com Add LUM8 case to GrGLCaps::getYUVAColorTypeFromBackendFormat
2019-07-31 aparchur@google.com [skottie] Rename TextValue to TextPropertyValue and make public.

Created with:
  gclient setdep -r src/third_party/skia@c876404e64d2

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


Bug: None
TBR=benjaminwagner@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': '6808e2d1faaccd6fc739f436c2470f199aa4d1a8',
+  'skia_revision': 'c876404e64d2fbbd5ebf0d6d01fe6ef48b1916a1',
 
   # When updating the Dart revision, ensure that all entries that are
   # dependencies of Dart are also updated to match the entries in the

engine/src/flutter/ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: 5c77485bb428ca206b9256629689ca90
+Signature: 3763324e9c500a7b191be0d11706f4d8
 
 UNUSED LICENSES: