Roll Skia from ac16760 to 45fe2e8 (4 revisions) (#19028)

https://skia.googlesource.com/skia.git/+log/ac16760df463..45fe2e8a9914

2020-06-12 [email protected] move methods to options class
2020-06-12 [email protected] [skjson] Reinstate initFastShortString
2020-06-12 [email protected] Add SkSurface flush call that takes a GrBackendSurfaceMutableState.
2020-06-12 [email protected] Allow printf-style formatting to be used in SK_ABORT.

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 [email protected] 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/+doc/master/autoroll/README.md

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': 'ac16760df46352bd3341d8be0ef3f70a273dbfe0',
+  'skia_revision': '45fe2e8a9914e775162995a8b40e4dbdd76af1f5',
 
   # 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: 23602ff03d68b0564c600da5a646ae6b
+Signature: 7efcc9af808ccc050dabbc48d23a6908
 
 UNUSED LICENSES: