Roll external/skia 796bc1db0..c069a5730 (13 commits)

https://skia.googlesource.com/skia.git/+log/796bc1db0..c069a5730

2018-06-19 brianosman@google.com added NIMA sample to showcase animations
2018-06-19 csmartdalton@google.com ccpr: Don't consider sub-pixel translation for caching on Android
2018-06-19 reed@google.com move imagefilters into separate dir and flag for build.gn
2018-06-19 rmistry@google.com Make infra failure message in Android compile bot more descriptive
2018-06-19 halcanary@google.com SkUtils: safe SkUTF16_NextUnichar
2018-06-19 fmalita@chromium.org Use SkJSONWriter for get_images_from_skps stats reporting
2018-06-19 brucewang@google.com Implement SkTypeface_FreeType::onMakeClone which overrides SkTypeface::onMakeClone.
2018-06-19 bsalomon@google.com Revert "Revert "Change how vertex/instance attributes are handled in geometry processors.""
2018-06-19 fmalita@chromium.org [skottie] Simplify Parse<SkPoint>
2018-06-19 herb@google.com Use SkGlyphRun instead of builder
2018-06-19 timliang@google.com Reland "Reland "added 565 to 8888 conversion for gpu LCD text rendering for macOS""
2018-06-19 robertphillips@google.com Move op memory storage to GrContext (take 2)
2018-06-19 caryclark@skia.org simplify confusing examples

The AutoRoll server is located here: https://android-master-roll.skia.org

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: I49f4731842a7d1d1a15fc4511eb9a9ce1627a773
Exempt-From-Owner-Approval: The autoroll bot does not require owner approval.