Roll third_party/externals/dawn 754c161fd366..303a3daf0dec (6 commits)
Roll third_party/externals/dawn 754c161fd366..303a3daf0dec (6 commits)

https://dawn.googlesource.com/dawn.git/+log/754c161fd366..303a3daf0dec

git log 754c161fd366..303a3daf0dec --date=short --first-parent --format='%ad %ae %s'
2020-04-30 bryan.bernhart@intel.com D3D12: Decouple descriptor heap allocations.
2020-04-30 yunchao.he@intel.com Add tests for resource tracking in compute - 1
2020-04-30 enga@chromium.org Suppress MSVC warnings about invalid switch values
2020-04-30 cwallez@chromium.org Enable -Wno-language-extension-token except on Windows
2020-04-30 cwallez@chromium.org Fix and enable -Wgnu-anonymous-struct
2020-04-30 cwallez@chromium.org Fix and enable -Wnested-anon-types

Also rolling transitive DEPS:
  https://chromium.googlesource.com/chromium/src/third_party/jinja2 b41863e42637..b41863e42637
  https://chromium.googlesource.com/chromium/src/third_party/markupsafe 8f45f5cfa000..8f45f5cfa000
  https://chromium.googlesource.com/external/github.com/KhronosGroup/glslang 39281fb710c3..39281fb710c3
  https://chromium.googlesource.com/external/github.com/google/shaderc 41f271e6139c..41f271e6139c

Created with:
  gclient setdep -r third_party/externals/dawn@303a3daf0dec

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dawn-skia-autoroll
Please CC 470c533e86f4f848c98c7e11fffc2d043494a401@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

Bug: None
Tbr: 470c533e86f4f848c98c7e11fffc2d043494a401@google.com
Change-Id: I387aa4e45352d3caa648fd9d37eb485e24561cb1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/286857
Reviewed-by: skia-autoroll <e034c62197df5622a9c1bef8b3e012f87a0a9840@skia-public.iam.gserviceaccount.com>
Commit-Queue: skia-autoroll <e034c62197df5622a9c1bef8b3e012f87a0a9840@skia-public.iam.gserviceaccount.com>

google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia