Roll Skia from e2c6940c36e4 to c3bdd1c597dc (4 revisions) (#21625)

https://skia.googlesource.com/skia.git/+log/e2c6940c36e4..c3bdd1c597dc

2020-10-06 robertphillips@google.com Separate mask creation from drawing in draw_shape_with_mask_filter
2020-10-06 kjlubick@google.com [canvaskit] Update to 0.18.1 (including typescript types/docs).
2020-10-06 kjlubick@google.com [canvaskit] Add docs/types for Skottie and Particles
2020-10-06 kjlubick@google.com [canvaskit] Add docs/types for paragraph

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 jvanverth@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/+doc/master/autoroll/README.md

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': 'e2c6940c36e4687cce431750b878c1dbe221c45d',
+  'skia_revision': 'c3bdd1c597dcbebebf4370d609581156a33ea5dc',
 
   # 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: c9add213539d0079fce22816e3ebf44a
+Signature: 373d1fc9c6213e2d6587b4273dbb6507
 
 UNUSED LICENSES: