Roll Skia from e9cf3f1740eb to 4f6b9d08b6d1 (2 revisions) (flutter/engine#44868)

https://skia.googlesource.com/skia.git/+log/e9cf3f1740eb..4f6b9d08b6d1

2023-08-18 johnstiles@google.com Add parentheses around ambiguous WGSL binary-op intrinsics.
2023-08-18 johnstiles@google.com Fix precedence level for WGSL ternary ops.

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 brianosman@google.com,egdaniel@google.com,jsimmons@google.com,rmistry@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

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': 'e9cf3f1740eb1a2cf847906fc59f956edf60226b',
+  'skia_revision': '4f6b9d08b6d1f2df8ce1b33767a82f55114f5bbc',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.

engine/src/flutter/ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: e62c72c1d135907897cf0fc8f6cb89d2
+Signature: a7bf0290bcaa4715daf7ee75c6fe7a7c
 
 ====================================================================================================
 LIBRARY: etc1