Roll Skia from 7839f66540b6 to 20f1b3462878 (1 revision) (#23129)

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': '7839f66540b6d5a1705bdd8817e65e7dfd4d397f',
+  'skia_revision': '20f1b3462878a98125aa03d4aa74b955fcf4acf3',
 
   # When updating the Dart revision, ensure that all entries that are
   # dependencies of Dart are also updated to match the entries in the