Roll external/skia 656cefe65..d004e0b55 (9 commits)

https://skia.googlesource.com/skia.git/+log/656cefe65..d004e0b55

2018-09-27 csmartdalton@google.com Cleanup resource flags
2018-09-27 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 122919bddd98..e8dd07969872 (4 commits)
2018-09-27 bungeman@google.com Detect macOS font smoothing behavior.
2018-09-27 egdaniel@google.com Remove assert about top left origin in lazy image generator unique key.
2018-09-27 herb@google.com Have Renderer use combined path code
2018-09-27 nathanrogers@google.com Fix a typo in SkISize comments
2018-09-27 bsalomon@google.com Reland "Change how GrTextureOp computes outset vertices."
2018-09-27 scroggo@google.com Make SkCodec truly default to sRGB
2018-09-27 borenet@google.com [infra] Add nightly UpdateGoDEPS

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: Ied2a3a68be5ad05e056be1b52968b9bed767d2cc
Exempt-From-Owner-Approval: The autoroll bot does not require owner approval.