Add fuzzing target to BUILD.gn

TEST=Built fuzzer in local checkout of Chromium with tint integrated.
BUG=dawn:14

Change-Id: I84aacd41f893070c3af40f5e640361e177689f9e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/20343
Reviewed-by: dan sinclair <dsinclair@google.com>
diff --git a/tint_overrides_with_defaults.gni b/tint_overrides_with_defaults.gni
index a8861ea..67f683c 100644
--- a/tint_overrides_with_defaults.gni
+++ b/tint_overrides_with_defaults.gni
@@ -17,6 +17,11 @@
 # This file contains Tint-related build flags.
 
 declare_args() {
+  # Path to tint checkout
+  if (!defined(tint_root_dir)) {
+    tint_root_dir = "//"
+  }
+
   # Path to spirv-tools checkout
   if (!defined(tint_spirv_tools_dir)) {
     tint_spirv_tools_dir = "//third_party/spirv-tools"
@@ -37,10 +42,6 @@
     tint_spirv_headers_dir = "//third_party/spirv-headers"
   }
 
-  # Generate documentation
-  # TODO(rharrison): Implement documentation support
-  tint_build_doc = false
-
   # Build the SPIR-V input reader
   if (!defined(tint_build_spv_reader)) {
     tint_build_spv_reader = false
@@ -61,10 +62,6 @@
     tint_build_wgsl_writer = false
   }
 
-  # Generate fuzzers
-  # TODO(rharrison): Implement fuzzer support
-  tint_build_fuzzers = false
-
   # Enable memory sanitizer
   # TODO(rharrison): Implement sanitizer support
   tint_enable_msan = false