Roll Skia from 7854da39b3c1 to 4fb13e026b6b (20 revisions) (flutter#24993)

Author: skia-flutter-autoroll

DEPS

@@ -27,7 +27,7 @@ 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': '7854da39b3c1cfabb6254d57a66616ad7bba9006',
+  'skia_revision': '4fb13e026b6b26e7714421b463b5d37ea9709ef5',
 
   # When updating the Dart revision, ensure that all entries that are
   # dependencies of Dart are also updated to match the entries in the

ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: fe422c84db4af6f17cb2517fc2e321f3
+Signature: 96d72ef81a389f349218327a68657c8f
 
 UNUSED LICENSES:
 
@@ -5173,6 +5173,7 @@ FILE: ../../../third_party/skia/src/sksl/SkSLMangler.h
 FILE: ../../../third_party/skia/src/sksl/SkSLOperators.cpp
 FILE: ../../../third_party/skia/src/sksl/SkSLOperators.h
 FILE: ../../../third_party/skia/src/sksl/ir/SkSLBinaryExpression.cpp
+FILE: ../../../third_party/skia/src/sksl/ir/SkSLBlock.cpp
 FILE: ../../../third_party/skia/src/sksl/ir/SkSLDoStatement.cpp
 FILE: ../../../third_party/skia/src/sksl/ir/SkSLExpressionStatement.cpp
 FILE: ../../../third_party/skia/src/sksl/ir/SkSLFieldAccess.cpp