Roll ANGLE from 4331ba7ac01d to a1ecebbc8338 (2 revisions)

https://chromium.googlesource.com/angle/angle.git/+log/4331ba7ac01d..a1ecebbc8338

2020-09-11 angle-autoroll@skia-public.iam.gserviceaccount.com Roll Vulkan-ValidationLayers from fcb7ecbe49c5 to 3114c91b037b (3 revisions)
2020-09-11 angle-autoroll@skia-public.iam.gserviceaccount.com Roll SwiftShader from b24900a1aa39 to 41974f57973e (1 revision)

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 ianelliott@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: ianelliott@google.com
Change-Id: Ia249efb96b18c2b842f5f54bea3f70b85aea4f8f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2406257Reviewed-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@{#806208}

DEPS

@@ -207,7 +207,7 @@ 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': '4331ba7ac01dc24f5477a04ed0ffce94b9a0d104',
+  'angle_revision': 'a1ecebbc833874ae4e478b14ea8cdc3db1fdd957',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.