Roll Skia from fb5e0ebef07c to 0b6bf1c9668e (2 revisions) (#21074)

https://skia.googlesource.com/skia.git/+log/fb5e0ebef07c..0b6bf1c9668e

2020-09-10 skia-autoroll@skia-public.iam.gserviceaccount.com Roll dawn from 0a1061da0c7f to 87f25134a8c1 (7 revisions)
2020-09-10 bsalomon@google.com Revert "Temporary hack to force text texture index varying to be float."

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 reed@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

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': 'fb5e0ebef07c998880d72d70910a532c8ae74049',
+  'skia_revision': '0b6bf1c9668ed85f8c7b25ef681f1952280a2cd1',
 
   # 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: f798b8691817cd4c2ef9f36d787924c2
+Signature: e892d5c47292f24218e211d8f2117bd6
 
 UNUSED LICENSES: