Roll src/third_party/dawn 8eb8385e2efc..720988d878a1 (1 commits)

https://dawn.googlesource.com/dawn.git/+log/8eb8385e2efc..720988d878a1

git log 8eb8385e2efc..720988d878a1 --date=short --no-merges --format='%ad %ae %s'
2019-10-08 mchiasson@gmail.com Fixed compilation issue on clang 6.x

Created with:
  gclient setdep -r src/third_party/dawn@720988d878a1

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dawn-chromium-autoroll
Please CC cwallez@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:dawn-linux-x64-deps-rel;luci.chromium.try:dawn-mac-x64-deps-rel;luci.chromium.try:dawn-win10-x64-deps-rel;luci.chromium.try:dawn-win10-x86-deps-rel
TBR=cwallez@google.com

Bug: None
Change-Id: I605b212e645380b4b12691e436d6bf71e40e5deb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1845886Reviewed-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@{#703620}

DEPS

@@ -302,7 +302,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.
-  'dawn_revision': '8eb8385e2efc6b4cc5e1d77fa888a64d9d6b0511',
+  'dawn_revision': '720988d878a186959e2b799ac8644c82759ef890',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.