Roll src/third_party/angle 83c24aa8a1cd..2f4a751866bc (4 commits)

https://chromium.googlesource.com/angle/angle.git/+log/83c24aa8a1cd..2f4a751866bc

git log 83c24aa8a1cd..2f4a751866bc --date=short --no-merges --format='%ad %ae %s'
2019-08-23 bsheedy@chromium.org Refactor perf tests to fix metric/story swapping
2019-08-23 geofflang@chromium.org Don't reset the texture size to zero in TextureGL::releaseTexImage on Mac.
2019-08-23 geofflang@chromium.org GL: Unset the bound PBO when initiailizing texture data.
2019-08-23 jonahr@google.com Suppress failure in MultisampleCompatibilityTest

Created with:
  gclient setdep -r src/third_party/angle@2f4a751866bc

The AutoRoll server is located here: https://autoroll.skia.org/r/angle-chromium-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


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_optional_gpu_tests_rel
TBR=jonahr@chromium.org,jonahr@google.com

Bug: chromium:923564,chromium:924618
Change-Id: I73ecb3a8d22328dc7ecea0bc0bc52f9cd8fd405c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1769648Reviewed-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@{#690128}

DEPS

@@ -172,7 +172,7 @@ 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': '83c24aa8a1cdc47c0b2ac52bcba53102bc097e1c',
+  'angle_revision': '2f4a751866bc19ffc9f19514c00246cdfea073ff',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.