Roll Skia from ae2171eba699 to 31df6806c06b (3 revisions)

https://skia.googlesource.com/skia.git/+log/ae2171eba699..31df6806c06b

2021-07-30 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2021-07-30 [email protected] draw atlas: using skvm
2021-07-30 [email protected] Reduce size of ChildPtr object.

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/+doc/main/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': 'ae2171eba6991eab7a212d33bf8e1203aec6f860',
+  'skia_revision': '31df6806c06b2949769a128fc5c1da8408ad1d1e',
 
   # 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: f1b1c5581e21b96c7e4665d7509dac1d
+Signature: d34bea5d8b6281442f16d18a3d6a6976
 
 UNUSED LICENSES: