Roll ANGLE from f54191ab6eeb to 9b0911a072fc (5 revisions)

https://chromium.googlesource.com/angle/angle.git/+log/f54191ab6eeb..9b0911a072fc

2021-04-03 jmadill@chromium.org Add GL_ANGLE_get_serialized_context_string.
2021-04-02 cnorthrop@google.com Tests: Add Dragon Raja trace
2021-04-02 jmadill@chromium.org Fix rapidjson build error in Skia.
2021-04-02 cnorthrop@google.com Capture/Replay: Support multi-digit context
2021-04-02 cclao@google.com Vulkan: Add baseLevel and generateMipmap test for immutable texture

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
Test: Test: Texture2DBaseMaxTestES3.GenerateMipmapAfterRebaseTest: Test: Texture2DBaseMaxTestES3.GenerateMipmapAfterRebaseImmutableTest: Test: Texture2DBaseMaxTestES3.PingPongBaseLevelImmutable
Change-Id: I66f2e10feff8d5c5918e3a38102ca22970f7903c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2802702
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Bot-Commit: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#869067}