Roll Skia from adc7ea94cada to 20829e37dfb8 (6 revisions) (flutter#179385)

https://skia.googlesource.com/skia.git/+log/adc7ea94cada..20829e37dfb8

2025-12-03 skia-autoroll@skia-public.iam.gserviceaccount.com Roll ANGLE
from 4f9af4659432 to 9e0f35674d95 (3 revisions)
2025-12-03 skia-autoroll@skia-public.iam.gserviceaccount.com Roll
SwiftShader from 04fbb7daf5a5 to 518a9f63228d (1 revision)
2025-12-03 skia-autoroll@skia-public.iam.gserviceaccount.com Roll Skia
Infra from 6c10ef924124 to f4ccba99d0aa (4 revisions)
2025-12-03 skia-autoroll@skia-public.iam.gserviceaccount.com Roll Dawn
from 31a119af4073 to 719fa5ff65ad (11 revisions)
2025-12-03 skia-autoroll@skia-public.iam.gserviceaccount.com Roll
vulkan-deps from 577557704db9 to 29d26a280798 (9 revisions)
2025-12-03
recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com
Roll recipe dependencies (trivial).

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 jsimmons@google.com,kjlubick@google.com,nicolettep@google.com
on the revert to ensure that a human
is aware of the problem.

To file a bug in Skia: https://bugs.chromium.org/p/skia/issues/entry
To file a bug in Flutter:
https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Author: engine-flutter-autoroll

DEPS

@@ -15,7 +15,7 @@ vars = {
   'flutter_git': 'https://flutter.googlesource.com',
   'skia_git': 'https://skia.googlesource.com',
   'llvm_git': 'https://llvm.googlesource.com',
-  'skia_revision': 'adc7ea94cada7bc2a5b21eee0664e7b2687f3612',
+  'skia_revision': '20829e37dfb8e58eac302337d338ba459aaf831f',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.