Roll src/third_party/angle a1f1cce6054f..2d1d9d35216b (2 commits)

https://chromium.googlesource.com/angle/angle.git/+log/a1f1cce6054f..2d1d9d35216b

git log a1f1cce6054f..2d1d9d35216b --date=short --first-parent --format='%ad %ae %s'
2020-01-27 syoussefi@chromium.org Fix atomicAdd validation w.r.t to swizzles
2020-01-27 jonahr@google.com Expose eglGetMscRateCHROMIUM from EGL_CHROMIUM_sync_control

Created with:
  gclient setdep -r src/third_party/angle@2d1d9d35216b

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 tobine@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/+/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
Bug: chromium:1042393
Tbr: tobine@google.com
Change-Id: I12a7b40a4b2b317c04e9d3539ff359bc8244ff60
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2023222Reviewed-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@{#735667}

DEPS

@@ -189,7 +189,7 @@ 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': 'a1f1cce6054f8e814d695c570e185ae68fcd662d',
+  'angle_revision': '2d1d9d35216b7fba0bde13ec033d1b9124ae571e',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.