Roll ANGLE from 30298dc25394 to 9dac86c9c458 (4 revisions)

https://chromium.googlesource.com/angle/angle.git/+log/30298dc25394..9dac86c9c458

2020-05-26 gbiv@chromium.org gen_proc_table: generate `const` tables
2020-05-26 kbr@chromium.org Remove requirement of OES_texture_half_float for EXT_color_buffer_half_float.
2020-05-26 kbr@chromium.org Emulate GL_EXT_sRGB on ES 3.0 devices without native support.
2020-05-26 jmadill@chromium.org Vulkan: Fix bad delete of swapchain.

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 ynovikov@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:1079475,chromium:1084580
Tbr: ynovikov@google.com
Change-Id: Iefc12e81d2178e0ba9c3c30ebcda9bb1efaf60ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2216761Reviewed-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@{#772037}

DEPS

@@ -190,7 +190,7 @@ 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': '30298dc2539484448965985e7b67dbe159f4b1f9',
+  'angle_revision': '9dac86c9c4587cc8d5d6c4ac1630d50890bebbe0',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.