Roll src/third_party/skia 9a8b846..f47717a (7 commits) (#12361)

https://skia.googlesource.com/skia.git/+log/9a8b846baf43..f47717ad8cc7

git log 9a8b846..f47717a --date=short --no-merges --format='%ad %ae %s'
2019-09-19 [email protected] Alter wacky_yuv_formats GM to skip rows if the required backing GPU format(s) aren't supported
2019-09-19 [email protected] Remove "experimental" comments regarding RG_F16 and RGBA_16161616
2019-09-19 [email protected] stifle warning in tValue2Scalar()
2019-09-19 [email protected] Set up prototype interface for MakeFromCAMetalLayer
2019-09-19 [email protected] Revert "Remove a usage of GrPixelConfig in SkGpuBlurUtils::GaussianBlur"
2019-09-19 [email protected] Use GrResourceProvider::MakeApprox for mask filter proxy sizes
2019-09-19 [email protected] Remove a usage of GrPixelConfig in SkGpuBlurUtils::GaussianBlur

Created with:
  gclient setdep -r src/third_party/skia@f47717ad8cc7

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 [email protected] 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
[email protected]

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': '9a8b846baf43752fa8cddbfa04b19b7707580d43',
+  'skia_revision': 'f47717ad8cc7623a641af8c1970bae3133d01849',
 
   # 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: f9408fc447605fa361acfd80fcff1feb
+Signature: fd364cc8acfef7a20d3d08a1e4c8bd2e
 
 UNUSED LICENSES:
 
@@ -3397,6 +3397,7 @@ FILE: ../../../third_party/skia/src/gpu/mtl/GrMtlSemaphore.h
 FILE: ../../../third_party/skia/src/gpu/mtl/GrMtlSemaphore.mm
 FILE: ../../../third_party/skia/src/gpu/vk/GrVkSecondaryCBDrawContext.cpp
 FILE: ../../../third_party/skia/src/gpu/vk/GrVkSecondaryCBDrawContext.h
+FILE: ../../../third_party/skia/src/image/SkSurface_GpuMtl.mm
 FILE: ../../../third_party/skia/src/shaders/SkRTShader.cpp
 FILE: ../../../third_party/skia/src/shaders/SkRTShader.h
 FILE: ../../../third_party/skia/src/sksl/SkSLDefines.h