Roll external/skia 670c6ec66..6ad5289ea (1 commits)

https://skia.googlesource.com/skia.git/+log/670c6ec66..6ad5289ea

2019-05-03 ethannicholas@google.com Revert "Child fragment processors are now written as separate functions"

The AutoRoll server is located here: https://autoroll-internal.skia.org/r/android-master-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, who should
be CC'd on the roll, and stop the roller if necessary.

Test: Presubmit checks will test this change.
Change-Id: Idc100925cccf3264b5a56cd80924c9557afa0a15
Exempt-From-Owner-Approval: The autoroll bot does not require owner approval.