Roll Skia from 3eb813e0cc13 to 18f4b1c7e31a (4 revisions)

https://skia.googlesource.com/skia.git/+log/3eb813e0cc13..18f4b1c7e31a

2020-09-23 adlai@google.com Revert "Migrate metal tools away from GrContext"
2020-09-23 skia-autoroll@skia-public.iam.gserviceaccount.com Roll ANGLE from f39e0f01aa1f to 2a09e89113af (18 revisions)
2020-09-23 skia-autoroll@skia-public.iam.gserviceaccount.com Roll Chromium from 1d6daec3 to 9a7bc8d5 (510 revisions)
2020-09-23 skia-autoroll@skia-public.iam.gserviceaccount.com Roll dawn from 52a588f3c9ba to 0b29732cd84f (5 revisions)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-autoroll
Please CC csmartdalton@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

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux-blink-rel;luci.chromium.try:linux-chromeos-compile-dbg;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Cq-Do-Not-Cancel-Tryjobs: true
Bug: None
Tbr: csmartdalton@google.com
Test: Test: Test: CQTest: Test: DrawCallPerfBenchmark.Run/vulkan_nullTest: Test: EGLContextASANTest.DestroyContextInUse/ES3_Vulkan
Change-Id: Ibd901cf6be8c41d26ea48ba9bcb5acf93d798d7c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2425902Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#809807}

DEPS

@@ -195,7 +195,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and whatever else without interference from each other.
-  'skia_revision': '3eb813e0cc134767a10e9efd4811fc519eccb280',
+  'skia_revision': '18f4b1c7e31a3543159fb0e6f9dd08521a3337d7',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.