Roll src/third_party/angle 6f23b4b7038e..e78527989c4c (2 commits)

https://chromium.googlesource.com/angle/angle.git/+log/6f23b4b7038e..e78527989c4c

git log 6f23b4b7038e..e78527989c4c --date=short --no-merges --format='%ad %ae %s'
2019-10-29 jmadill@chromium.org Vulkan: Clean up redundant vk:: prefixes.
2019-10-29 jmadill@chromium.org Vulkan: Move readPixels logic to ImageHelper.

Created with:
  gclient setdep -r src/third_party/angle@e78527989c4c

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/+/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_optional_gpu_tests_rel
TBR=ynovikov@google.com

Bug: None
Change-Id: I12cfa5fd4c73df18c7e3218db6a9beb9ebcdc3ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1885730Reviewed-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@{#710213}

DEPS

@@ -184,7 +184,7 @@ 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': '6f23b4b7038e0b5baa75db310c1988a7b85f1a3a',
+  'angle_revision': 'e78527989c4c8e2b517a77647843fafeb74e283a',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.