Roll ANGLE from 939fcd1a14f5 to 5850c748b480 (2 revisions)

https://chromium.googlesource.com/angle/angle.git/+log/939fcd1a14f5..5850c748b480

2020-11-26 syoussefi@chromium.org Vulkan: Emulated RGB copies in compute
2020-11-26 syoussefi@chromium.org Add a sample shading test to verify FS invocation per sample

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/angle-chromium-autoroll
Please CC jmadill@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_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win-asan;luci.chromium.try:win_optional_gpu_tests_rel;luci.chromium.try:linux-swangle-try-x64;luci.chromium.try:win-swangle-try-x86
Bug: None
Tbr: jmadill@google.com
Change-Id: Icd997fc6d0f73e28bc32799a18a4cace701e6d97
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2561837Reviewed-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@{#831286}

DEPS

@@ -212,7 +212,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling ANGLE
   # and whatever else without interference from each other.
-  'angle_revision': '939fcd1a14f5ddc43e300bcb2d5d1f680c50ab85',
+  'angle_revision': '5850c748b480ae13159323ce2b3a09a36355711b',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.