Roll src/third_party/skia bf1d4effe171..19547c91b983 (4 commits) (#9942)

https://skia.googlesource.com/skia.git
/compare/bf1d4effe171..19547c91b983

git log bf1d4effe17191b7ce5537ed43421cec34496bfb..19547c91b9837eeff1c5005dd7b047bb151fb628 --date=short --no-merges --format=%ad %ae %s
2019-07-19 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update Go deps
2019-07-19 skia-autoroll@skia-public.iam.gserviceaccount.com Roll ../src a87860686ec4..e02114c8fa90 (407 commits)
2019-07-18 mtklein@google.com assign tmp and dst only as needed
2019-07-17 nigeltao@google.com Remove deprecated Wuffs io_buffer::reader calls

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 (nifong@google.com), and stop
the roller if necessary.

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': 'bf1d4effe17191b7ce5537ed43421cec34496bfb',
+  'skia_revision': '19547c91b9837eeff1c5005dd7b047bb151fb628',
 
   # 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: b06d33d4a4981bd00be76e1f18d86dd9
+Signature: 42d8c735b4876e0d64e59b4253f38a07
 
 UNUSED LICENSES: