Roll Dawn from 839324a331c0 to 643f2aad4305 (2 revisions)

https://dawn.googlesource.com/dawn.git/+log/839324a331c0..643f2aad4305

2023-02-18 bclayton@google.com tint/reader/wgsl: Remove type keywords
2023-02-18 dneto@google.com spirv-reader: don't hoist opaque objects

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 bajones@google.com,cwallez@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Dawn: https://bugs.chromium.org/p/dawn/issues/entry
To file a bug in Chromium: https://bugs.chromium.org/p/chromium/issues/entry

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/+doc/main/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: bajones@google.com
Change-Id: I876f9466fd65a80fc37897934354951b57fc9ac7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4267330
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Bot-Commit: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1107164}

DEPS

@@ -426,7 +426,7 @@ 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': '839324a331c0feaaceec2122b3bb99e6423f3f49',
+  'dawn_revision': '643f2aad43055f2a2f8576c2ef4fbea958317584',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.