Roll src/third_party/angle 7d45184d4baa..8247ae787cc4 (5 commits)

https://chromium.googlesource.com/angle/angle.git/+log/7d45184d4baa..8247ae787cc4

git log 7d45184d4baa..8247ae787cc4 --date=short --first-parent --format='%ad %ae %s'
2020-01-22 syoussefi@chromium.org Manually roll spirv-headers
2020-01-22 syoussefi@chromium.org Add support for layout(early_fragment_tests) in;
2020-01-22 syoussefi@chromium.org Row-major test: Clarify std140's stride calculation
2020-01-22 syoussefi@chromium.org Add support for non-float mix
2020-01-22 courtneygo@google.com Update expectations after dEQP test fixes

Created with:
  gclient setdep -r src/third_party/angle@8247ae787cc4

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 timvp@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:1044061
Tbr: timvp@google.com
Change-Id: I00622f4eeeccb4864f0e6805347ce9657d2d0bdc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2015143Reviewed-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@{#734292}

DEPS

@@ -193,7 +193,7 @@ 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': '7d45184d4baaccb6719b5f2f8c30311c0a54582e',
+  'angle_revision': '8247ae787cc41cf203bffa90bd5ea44c02ba6a75',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.