Roll src/third_party/dawn dc9f1e680699..867f72058a4f (2 commits)

https://dawn.googlesource.com/dawn.git/+log/dc9f1e680699..867f72058a4f

git log dc9f1e680699..867f72058a4f --date=short --no-merges --format='%ad %ae %s'
2019-10-02 enga@chromium.org Add missing "strlen" parameter for Device InjectError command.
2019-10-02 enga@chromium.org dawn_wire: Only generate has_member for optional members

Created with:
  gclient setdep -r src/third_party/dawn@867f72058a4f

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: chromium:1004368,chromium:1009166
Change-Id: Idf72b8fa81d01508217bd08fa25cbcd625f34dd8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1835277Reviewed-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@{#701988}

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': 'dc9f1e68069917f29d552d9cb0b7993fcb7c4059',
+  'dawn_revision': '867f72058a4f6b901524efe484611e1e319c80fb',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.