Roll external/skia 767fddfcc..ed5e73cdf (9 commits)

https://skia.googlesource.com/skia.git/+log/767fddfcc..ed5e73cdf

2018-08-16 allanmac@google.com Merge Vulkan Compute work into master.
2018-08-16 kjlubick@google.com Make verbose.log optional in upload_dm_results
2018-08-16 reed@google.com move patheffect virtuals to protected and rename
2018-08-16 recipe-roller@chromium.org Roll recipe dependencies (trivial).
2018-08-16 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/angle2 3fd614d06e50..f0e3c19a0c02 (1 commits)
2018-08-16 skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/skcms f1e2b45d18fa..b2fffd2ecf2e (1 commits)
2018-08-16 reed@google.com add more tests for SkCubicMap
2018-08-16 bungeman@google.com Beautify GlyphTransform sample.
2018-08-16 mtklein@google.com don't adapt gray colors to 565

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: I5965bf1544466c362558614b1f3476be8aa0481d
Exempt-From-Owner-Approval: The autoroll bot does not require owner approval.