Add Tint to third_party/

Tint is an implementation of WGSL, the shading for WebGPU, that Dawn,
our implementation of WebGPU, uses.

Requires adding dawn_enable_wgsl=true to args.gn currently to use.

BUG=1070645

Change-Id: I733cc23f3ca25c8943082564f277234d22a3662d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2248753
Auto-Submit: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Will Harris <wfh@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Cr-Commit-Position: refs/heads/master@{#788699}

DEPS

@@ -354,6 +354,9 @@ vars = {
   # the commit queue can handle CLs rolling ukey2
   # and whatever else without interference from each other.
   'ukey2_revision': '0275885d8e6038c39b8a8ca55e75d1d4d1727f47',
+  # the commit queue can handle CLs rolling feed
+  # and whatever else without interference from each other.
+  'tint_revision': '919011af0a2ae1b663aae0aaa4083a3f9f13e66d',
 
   # TODO(crbug.com/941824): The values below need to be kept in sync
   # between //DEPS and //buildtools/DEPS, so if you're updating one,
@@ -785,6 +788,9 @@ deps = {
   'src/third_party/dawn':
     Var('dawn_git') + '/dawn.git' + '@' +  Var('dawn_revision'),
 
+  'src/third_party/tint/src':
+    Var('dawn_git') + '/tint.git' + '@' +  Var('tint_revision'),
+
   'src/third_party/glfw/src':
     Var('chromium_git') + '/external/github.com/glfw/glfw.git@' +  '2de2589f910b1a85905f425be4d32f33cec092df',
 

build_overrides/dawn.gni

@@ -11,5 +11,6 @@ dawn_shaderc_dir = "//third_party/shaderc/src"
 dawn_spirv_cross_dir = "//third_party/spirv-cross/spirv-cross"
 dawn_spirv_tools_dir = "//third_party/SPIRV-Tools/src"
 dawn_swiftshader_dir = "//third_party/swiftshader"
+dawn_tint_dir = "//third_party/tint/src"
 dawn_vulkan_validation_layers_dir =
     "//third_party/angle/third_party/vulkan-validation-layers/src"

build_overrides/tint.gni

+# Copyright 2020 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+tint_root_dir = "//third_party/tint/src"
+tint_spirv_tools_dir = "//third_party/SPIRV-Tools/src"
+tint_googletest_dir = "//third_party/googletest/src"
+tint_spirv_headers_dir = "//third_party/spirv-headers/src"
+
+tint_build_spv_reader = true
+tint_build_spv_writer = true
+tint_build_wgsl_reader = true
+tint_build_wgsl_writer = true

third_party/.gitignore

@@ -218,6 +218,7 @@
 /swiftshader/
 /syzygy
 /syzygy/binaries
+/tint/src
 /tsan/
 /turbine/src
 /turbine/*.jar

third_party/tint/OWNERS

+cwallez@chromium.org
+dsinclair@chromium.org
+kainino@chromium.org

third_party/tint/README.chromium

+Name: Tint
+Short Name: tint
+URL: https://dawn.googlesource.com/tint
+Version: 0
+Revision: 919011af0a2ae1b663aae0aaa4083a3f9f13e66d
+License: Apache 2.0
+License File: LICENSE
+Security Critical: yes
+
+Description:
+Tint is an implementation of WGSL, the WebGPU shading language. It is used by
+Dawn, an implementation for WebGPU, in Chromium. Specifically it provides
+facilities for conversion to/from WGSL from other shading languages like SPIR-V.