Roll Skia from 557183808708 to 68dbdbdc2e49 (1 revision) (flutter#38420)

https://skia.googlesource.com/skia.git/+log/557183808708..68dbdbdc2e49

2022-12-20 skia-autoroll@skia-public.iam.gserviceaccount.com Roll vulkan-deps from f13305cd994c to 28ede018d9d4 (3 revisions)

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,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://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

@@ -18,7 +18,7 @@ vars = {
   'llvm_git': 'https://llvm.googlesource.com',
   # OCMock is for testing only so there is no google clone
   'ocmock_git': 'https://github.com/erikdoe/ocmock.git',
-  'skia_revision': '55718380870880e3b9a4f9b96b607a5d6085d38c',
+  'skia_revision': '68dbdbdc2e49dd03eb10ec7ba1e1f32cd5227d92',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.