Roll src/third_party/skia 1bd245b91801..5b257abb87d2 (5 commits) (#7656)

https://skia.googlesource.com/skia.git/%2Blog/1bd245b91801..5b257abb87d2

git log 1bd245b9180147d85b6ead60a04116e0333ad37f..5b257abb87d2085b7f36fd5bc8f4a78a73942b2a --date=short --no-merges --format=%ad %ae %s
2019-01-30 reed@google.com change measureText impl to first convert to glyphs
2019-01-30 egdaniel@google.com Add hardware buffer unit test from old skqp to skia.
2019-01-31 bsalomon@google.com Update Metal unit test blacklist after adding new promise image tests
2019-01-30 bsalomon@google.com Add option to skip intermediate release/fulfill calls for promise images.
2019-01-30 michaelludwig@google.com Add new thin anti-aliasing demo

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff (borenet@google.com), and stop
the roller if necessary.

DEPS

@@ -23,7 +23,7 @@ vars = {
   'fuchsia_git': 'https://fuchsia.googlesource.com',
   'github_git': 'https://github.com',
   'skia_git': 'https://skia.googlesource.com',
-  'skia_revision': '1bd245b9180147d85b6ead60a04116e0333ad37f',
+  'skia_revision': '5b257abb87d2085b7f36fd5bc8f4a78a73942b2a',
 
   # 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

-Signature: 2b63dcfcce51383860e5d143033bfdee
+Signature: 922dfed5a65815e76f694eaba4265b33
 
 UNUSED LICENSES:
 
@@ -5036,6 +5036,7 @@ FILE: ../../../third_party/skia/include/private/GrContext_Base.h
 FILE: ../../../third_party/skia/include/private/GrImageContext.h
 FILE: ../../../third_party/skia/include/private/GrRecordingContext.h
 FILE: ../../../third_party/skia/modules/sksg/src/SkSGTransformPriv.h
+FILE: ../../../third_party/skia/samplecode/SampleThinAA.cpp
 FILE: ../../../third_party/skia/src/core/SkDescriptor.cpp
 FILE: ../../../third_party/skia/src/gpu/GrBaseContextPriv.h
 FILE: ../../../third_party/skia/src/gpu/GrContextThreadSafeProxy.cpp