Manual land of roll - two bots on luci-engine are red due to flakes.

https://skia.googlesource.com/skia.git/+log/17c5b7024297..e1e240804211

2020-08-20 skia-autoroll@skia-public.iam.gserviceaccount.com Roll Chromium from ff3c275665f9 to e45f0c4dce5a (503 revisions)
2020-08-20 skia-autoroll@skia-public.iam.gserviceaccount.com Roll dawn from b54c82ed3948 to eff9ef0f2212 (2 revisions)
2020-08-20 skia-autoroll@skia-public.iam.gserviceaccount.com Roll ANGLE from 699bcde0b729 to 5dff6075d29f (19 revisions)
2020-08-20 mtklein@google.com Revert "Add utilities to SkGeometry for quad and cubic rotation angles"
2020-08-20 mtklein@google.com Revert "remove sksl interpreter guards"
2020-08-20 ethannicholas@google.com Revert "Added support for the 'inline' hint on SkSL functions"
2020-08-20 ethannicholas@google.com Revert "SkSL CPP and H backends no longer emitted in non-dev builds"
2020-08-20 ethannicholas@google.com Revert "SkSL now supports uniform array types"
2020-08-19 csmartdalton@google.com Move GrWangsFormula::nextlog2 to sk_float_nextlog2
2020-08-19 johnstiles@google.com Remove final vestiges of sk_InColor.
2020-08-19 ethannicholas@google.com SkSL now supports uniform array types
2020-08-19 csmartdalton@google.com Add utilities to SkGeometry for quad and cubic rotation angles
2020-08-19 mtklein@google.com update placeholder approx op count
2020-08-19 johnstiles@google.com Remove sk_InColor from unit tests.
2020-08-19 adlai@google.com Remove GrContext variant of SkImageGenerator::isValid
2020-08-19 johnstiles@google.com Fix simplification of switch statements with casts.
2020-08-19 reed@google.com pass 'nested' bool to approximateOpCount
2020-08-19 mtklein@google.com clean up SK_LATE_DITHER
2020-08-19 ethannicholas@google.com Added support for the 'inline' hint on SkSL functions
2020-08-19 mtklein@google.com remove sksl interpreter guards

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 stani@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

* Revert harfbuzz 2.7.0, which broke Khmer rendering