Roll src/third_party/dawn 42b3b9c4131a..7ecb9268dfeb (1 commits)

https://dawn.googlesource.com/dawn.git/+log/42b3b9c4131a..7ecb9268dfeb

git log 42b3b9c4131a..7ecb9268dfeb --date=short --first-parent --format='%ad %ae %s'
2019-12-04 rharrison@chromium.org Merge two calls to InitializeHLSL into one

Created with:
  gclient setdep -r src/third_party/dawn@7ecb9268dfeb

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
Bug: None
Tbr: cwallez@google.com
Change-Id: I8f182238eaf67582e1b3f2caed721838925e06d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1952175Reviewed-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@{#721889}

DEPS

@@ -303,7 +303,7 @@ 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': '42b3b9c4131a151941d35c5a19070517ccb492a3',
+  'dawn_revision': '7ecb9268dfebb1e9a79e0dab95d2e9f4ecbffe44',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.