Roll src/third_party/skia 70ebd9ca0616..9c8ad0316147 (9 commits) (#7646)

https://skia.googlesource.com/skia.git/%2Blog/70ebd9ca0616..9c8ad0316147

git log 70ebd9ca0616f54450a38d4f0f952810595a441b..9c8ad031614760e8256d4e2eb97ebdef8c067cd2 --date=short --no-merges --format=%ad %ae %s
2019-01-30 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader cda0cf9d8112..ddcbdc51f2aa (1 commits)
2019-01-30 jvanverth@google.com Fix screen invalidation on MacOS
2019-01-30 mtklein@google.com remove shadeSpan4f()
2019-01-30 herb@google.com Revert "make third_party() static libraries"
2019-01-30 mtklein@google.com remove Sk4x4f.h -- dead code
2019-01-30 robertphillips@google.com Add outline of new GrContext hierarchy
2019-01-30 mtklein@google.com remove burst mode in SkRPBlitter
2019-01-30 bsalomon@google.com Remove legacy texture-backed promise image interface.
2019-01-30 mtklein@google.com add Leon's gradient to p3 GM

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 (borenet@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': '70ebd9ca0616f54450a38d4f0f952810595a441b',
+  'skia_revision': '9c8ad031614760e8256d4e2eb97ebdef8c067cd2',
 
   # 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: 9fbc0d30a3a9de96a9a329b406654e52
+Signature: eeafbd18a447691d6b04247ac2d41ecc
 
 UNUSED LICENSES:
 
@@ -1334,7 +1334,6 @@ FILE: ../../../third_party/skia/src/compute/skc/styling.c
 FILE: ../../../third_party/skia/src/compute/skc/styling.h
 FILE: ../../../third_party/skia/src/compute/skc/styling_types.h
 FILE: ../../../third_party/skia/src/compute/skc/tile.h
-FILE: ../../../third_party/skia/src/core/Sk4x4f.h
 FILE: ../../../third_party/skia/src/core/SkATrace.cpp
 FILE: ../../../third_party/skia/src/core/SkATrace.h
 FILE: ../../../third_party/skia/src/core/SkAnnotationKeys.h
@@ -5033,9 +5032,18 @@ ORIGIN: ../../../third_party/skia/gm/skbug_8664.cpp + ../../../third_party/skia/
 TYPE: LicenseType.bsd
 FILE: ../../../third_party/skia/gm/skbug_8664.cpp
 FILE: ../../../third_party/skia/include/gpu/GrContextThreadSafeProxy.h
+FILE: ../../../third_party/skia/include/private/GrContext_Base.h
+FILE: ../../../third_party/skia/include/private/GrImageContext.h
+FILE: ../../../third_party/skia/include/private/GrRecordingContext.h
 FILE: ../../../third_party/skia/modules/sksg/src/SkSGTransformPriv.h
 FILE: ../../../third_party/skia/src/core/SkDescriptor.cpp
+FILE: ../../../third_party/skia/src/gpu/GrBaseContextPriv.h
 FILE: ../../../third_party/skia/src/gpu/GrContextThreadSafeProxy.cpp
+FILE: ../../../third_party/skia/src/gpu/GrContext_Base.cpp
+FILE: ../../../third_party/skia/src/gpu/GrImageContext.cpp
+FILE: ../../../third_party/skia/src/gpu/GrImageContextPriv.h
+FILE: ../../../third_party/skia/src/gpu/GrRecordingContext.cpp
+FILE: ../../../third_party/skia/src/gpu/GrRecordingContextPriv.h
 FILE: ../../../third_party/skia/src/gpu/vk/GrVkSecondaryCBDrawContext.cpp
 FILE: ../../../third_party/skia/src/gpu/vk/GrVkSecondaryCBDrawContext.h
 FILE: ../../../third_party/skia/src/sksl/SkSLDefines.h