Roll ANGLE from 121d985642fd to 6b2639b023f9 (3 revisions)

https://chromium.googlesource.com/angle/angle.git/+log/121d985642fd..6b2639b023f9

2020-09-02 jonahr@google.com Workaround to disable OES_get_program_binary
2020-09-02 syoussefi@chromium.org Gracefully fail end2end tests if no window support
2020-09-02 sugoi@chromium.org Revert "Make copyTexImage2D robust when source area is out of bounds"

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 cwallez@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: chromium:1034840
Tbr: cwallez@google.com
Change-Id: I9e81e85a97607e54f990511638fe9a7a2a3a9b0d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2391400Reviewed-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@{#803967}

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': '121d985642fd5599e95221f70140dc5df4137bdb',
+  'angle_revision': '6b2639b023f90759d6be3607186e9b71530f0a85',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.