Roll Skia from c1b6b6c615a7 to d9a7c5953df3 (2 revisions) (#26089)

https://skia.googlesource.com/skia.git/+log/c1b6b6c615a7..d9a7c5953df3

2021-05-12 skia-autoroll@skia-public.iam.gserviceaccount.com Roll Chromium from 5d4a69b076e1 to 51f0f14b5681 (472 revisions)
2021-05-12 skia-autoroll@skia-public.iam.gserviceaccount.com Roll Dawn from e2f083e4b0f5 to f0fdfa0d61df (1 revision)

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 robertphillips@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/+doc/master/autoroll/README.md

Author: skia-flutter-autoroll

DEPS

@@ -27,7 +27,7 @@ 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': 'c1b6b6c615a79fc0a748be87e90a2cf1f10f5037',
+  'skia_revision': 'd9a7c5953df3acafbfc03a2bf5ef89e67f75cfb6',
 
   # 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: 297d58b99e0bf5bc6a64d85aeab0ed70
+Signature: c8afa8c576b40af414fa76e7692a71fd
 
 UNUSED LICENSES: