Roll src/third_party/dawn 0ecc48ecb7a1..631f4258a1ac (6 commits)

https://dawn.googlesource.com/dawn.git/+log/0ecc48ecb7a1..631f4258a1ac

git log 0ecc48ecb7a1..631f4258a1ac --date=short --first-parent --format='%ad %ae %s'
2020-01-16 enga@chromium.org Suppress Depth32TextureCreationDepthClears on D3D12 NVIDIA
2020-01-16 enga@chromium.org OpenGL: Simplify lazy clear of render pass attachments
2020-01-16 enga@chromium.org D3D12: Simplify lazy clear of render pass attachments
2020-01-16 enga@chromium.org Vulkan: Simplify lazy clear of render pass attachments
2020-01-16 enga@chromium.org Directly load Swiftshader if no Vulkan driver is available
2020-01-16 enga@chromium.org Metal: Implement lazy texture clears

Created with:
  gclient setdep -r src/third_party/dawn@631f4258a1ac

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: I2b0e54f5eb773ac971bd09de80f0a648f7f59932
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003818Reviewed-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@{#732320}

DEPS

@@ -312,7 +312,7 @@ 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': '0ecc48ecb7a1353b9e1a3cd9d3a125f6a770477c',
+  'dawn_revision': '631f4258a1ace016d6a10ebf7ff127ea46be8575',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.