Roll ANGLE from e689d3164f34 to 4909d08c1410 (3 revisions)

https://chromium.googlesource.com/angle/angle.git/+log/e689d3164f34..4909d08c1410

2020-08-21 cclao@google.com Vulkan: Rename mStagingBufferStorage to mStagingBuffer
2020-08-21 jmadill@chromium.org Vulkan: Restart RenderPasses in DS read-only mode.
2020-08-21 cclao@google.com Vulkan: Use context staging buffer for immutable texture update

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 cnorthrop@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: cnorthrop@google.com
Change-Id: I4b9181ca884733500d3fa0533ce6ce8b69b8ffce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2368545Reviewed-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@{#800481}

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': 'e689d3164f3457ee8dcceb0a129233638b16c32a',
+  'angle_revision': '4909d08c1410343d8f27b45f623c5eddccafdc3f',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.