Roll Dawn from 6a029fc9d84e to 55c85f66d2fd (3 revisions)

https://dawn.googlesource.com/dawn.git/+log/6a029fc9d84e..55c85f66d2fd

2020-05-27 hao.x.li@intel.com Query API: Extensions
2020-05-27 xinghua.cao@intel.com Check FP16 support on vulkan backend
2020-05-27 jiajie.hu@intel.com Set a default value for dawn_glm_dir like other GN build overrides

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/+doc/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: I10c75bd1e7f98df9b252e2f9c020afadd8fa06ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2217329Reviewed-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@{#772151}

DEPS

@@ -301,7 +301,7 @@ 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': '6a029fc9d84edb5ddfb88c6be6c02c5dbc1ccd63',
+  'dawn_revision': '55c85f66d2fd201717ce667bf96c0949b32e9623',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.