Roll Skia from b55bd60ed95b to 8cd449e4953b (8 revisions) (flutter#177405)

https://skia.googlesource.com/skia.git/+log/b55bd60ed95b..8cd449e4953b

2025-10-22 skia-autoroll@skia-public.iam.gserviceaccount.com Roll
vulkan-deps from a707284d1dae to 45612592f686 (3 revisions)
2025-10-22 kjlubick@google.com Delete obsolete build_overrides for dawn
2025-10-22
recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com
Roll recipe dependencies (trivial).
2025-10-22 briansalomon@gmail.com DM builds with graphite enabled and
ganesh disabled
2025-10-22 mike@reedtribe.org Have path transform return optional?
2025-10-22 michaelludwig@google.com [graphite] Move away from
optional<SkBlendMode>
2025-10-22 mike@reedtribe.org Simplify builder state
2025-10-22 fmalita@google.com Add a SkRRect::MakeRectRadii helper

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
chinmaygarde@google.com,jmbetancourt@google.com,kjlubick@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': 'b55bd60ed95bfc997ed1eaa445f8c5f0fa6e6820',
+  'skia_revision': '8cd449e4953b56fe829b2aaa99ef80cc1c72abbf',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.