Add in basic BUILD.gn and additional DEPS

This is a minimal config that gets us building the tint binary from samples/

BUG=tint:2

Change-Id: Ifafa903e99a34f1c47177eb954df69ecbe70cb36
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/19106
Reviewed-by: dan sinclair <dsinclair@google.com>
diff --git a/tint.gni b/tint.gni
new file mode 100644
index 0000000..8986907
--- /dev/null
+++ b/tint.gni
@@ -0,0 +1,43 @@
+# Copyright 2020 The Tint Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import("//build_overrides/tint.gni")
+
+# This file contains Tint-related build flags.
+
+declare_args() {
+  # Generate documentation
+  # TODO(rharrison): Implement documentation support
+  tint_build_doc = false
+
+  # Generate SPIR-V input parser
+  # TODO(rharrison): Implement SPIR-V input parser support
+  tint_build_spv_parser = false
+
+  # Generate fuzzers
+  # TODO(rharrison): Implement fuzzer support
+  tint_build_fuzzers = false
+
+  # Enable memory sanitizer
+  # TODO(rharrison): Implement sanitizer support
+  tint_enable_msan = false
+
+  # Enable address sanitizer
+  # TODO(rharrison): Implement sanitizer support
+  tint_enable_msan = false
+
+  # Enable undefined behaviour sanitizer
+  # TODO(rharrison): Implement sanitizer support
+  tint_enable_ubsan = false
+}
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