Roll src/third_party/skia 274a766..b60ec7f (9 commits) (#14256)

https://skia.googlesource.com/skia.git/+log/274a766baf2f..b60ec7f98b08

git log 274a766..b60ec7f --date=short --first-parent --format='%ad %ae %s'
2019-12-08 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update SKP version
2019-12-06 herb@google.com Fix fix chrome build bots
2019-12-06 bungeman@google.com Protect against invalid text.
2019-12-06 herb@google.com Change from std to skstd for aligned_union_t
2019-12-06 herb@google.com Turn GrTextBlob vertices into actual structs
2019-12-06 jvanverth@google.com Fix typo in box-plane test.
2019-12-06 brianosman@google.com Switch to float vertex colors for wide color vertex attribs
2019-12-06 michaelludwig@google.com Avoid implicit conversion back to int
2019-12-06 kjlubick@google.com [canvaskit] Add _RTShaderFactory for demos

Created with:
  gclient setdep -r src/third_party/skia@b60ec7f98b08

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 djsollen@google.com on the revert to ensure that a human
is aware of the problem.

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/+/master/autoroll/README.md

Bug: None
Tbr: djsollen@google.com

Author: skia-flutter-autoroll

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': '274a766baf2fa26e3c3b75174a3ab406b611e5c7',
+  'skia_revision': 'b60ec7f98b081c593c439da2f4619c192e26aa98',
 
   # 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: 576dbf072c4630d253f61b4a71884bc1
+Signature: ccf7b6206918956bb9c05a75904a4da0
 
 UNUSED LICENSES: