Roll src/third_party/skia 6c8f5b31ac49..6db27c28c61e (4 commits) (#8802)

https://skia.googlesource.com/skia.git
/%2Blog/6c8f5b31ac49..6db27c28c61e

git log 6c8f5b31ac49be07ce68efb176a803a38810cb44..6db27c28c61e7598b4baff4ac70a44be85003a83 --date=short --no-merges --format=%ad %ae %s
2019-05-01 robertphillips@google.com Reduce opList splitting by default in Skia
2019-05-01 robertphillips@google.com Revert "remove legacy 255-biased colormatrix"
2019-05-01 brianosman@google.com Remove shader text trace events and simplify the SKSL/GLSL printing code
2019-04-26 reed@google.com remove legacy 255-biased colormatrix

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 (ethannicholas@google.com), and stop
the roller if necessary.

DEPS

@@ -23,7 +23,7 @@ vars = {
   'fuchsia_git': 'https://fuchsia.googlesource.com',
   'github_git': 'https://github.com',
   'skia_git': 'https://skia.googlesource.com',
-  'skia_revision': '6c8f5b31ac49be07ce68efb176a803a38810cb44',
+  'skia_revision': '6db27c28c61e7598b4baff4ac70a44be85003a83',
 
   # 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: c6d375ee7d72711d189df15f4781690e
+Signature: 42d25f91c1f7145cd4d4050c91a1085b
 
 UNUSED LICENSES:
 
@@ -3963,8 +3963,6 @@ FILE: ../../../third_party/skia/src/gpu/GrRectanizer_pow2.h
 FILE: ../../../third_party/skia/src/gpu/GrRectanizer_skyline.h
 FILE: ../../../third_party/skia/src/gpu/GrResourceCache.cpp
 FILE: ../../../third_party/skia/src/gpu/GrResourceCache.h
-FILE: ../../../third_party/skia/src/gpu/GrSKSLPrettyPrint.cpp
-FILE: ../../../third_party/skia/src/gpu/GrSKSLPrettyPrint.h
 FILE: ../../../third_party/skia/src/gpu/GrSurfacePriv.h
 FILE: ../../../third_party/skia/src/gpu/GrTRecorder.h
 FILE: ../../../third_party/skia/src/gpu/GrTexturePriv.h
@@ -5362,6 +5360,8 @@ FILE: ../../../third_party/skia/modules/particles/src/SkParticleDrawable.cpp
 FILE: ../../../third_party/skia/modules/particles/src/SkParticleEffect.cpp
 FILE: ../../../third_party/skia/modules/particles/src/SkReflected.cpp
 FILE: ../../../third_party/skia/src/core/SkColorFilterPriv.h
+FILE: ../../../third_party/skia/src/gpu/GrShaderUtils.cpp
+FILE: ../../../third_party/skia/src/gpu/GrShaderUtils.h
 FILE: ../../../third_party/skia/src/gpu/gl/GrGLAssembleGLESInterfaceAutogen.cpp
 FILE: ../../../third_party/skia/src/gpu/gl/GrGLAssembleGLInterfaceAutogen.cpp
 FILE: ../../../third_party/skia/src/gpu/gl/GrGLAssembleHelpers.cpp