Disable fuzzing generation for //gpu/ipc/common:vulkan_interfaces.

This CL disables fuzzing generation for the vulkan mojom target
when enable_vulkan isn't set, since the generated MojoLPM fuzzer
code will expect the vulkan headers to be available.

This is a cherrypick/split from
https://chromium-review.googlesource.com/c/chromium/src/+/2108507

Change-Id: Ia0e3d0f5d19994021bcbc94739ea51a802bd5877
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2120476
Commit-Queue: Mark Brand <markbrand@google.com>
Reviewed-by: Ken Rockot <rockot@google.com>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753565}

gpu/ipc/common/BUILD.gn

@@ -250,6 +250,14 @@ mojom("gpu_preferences_interface") {
 
 mojom("vulkan_interface") {
   generate_java = true
+
+  # TODO(crbug.com/1062364): This interface code is used by some javascript targets even
+  # when vulkan isn't enabled, but the C++ fuzzer code will fail to compile if
+  # the headers aren't available.
+  if (!enable_vulkan) {
+    enable_fuzzing = false
+  }
+
   sources = [
     "vulkan_info.mojom",
     "vulkan_types.mojom",

mojo/public/tools/bindings/mojom.gni

@@ -596,9 +596,9 @@ template("mojom") {
 
   write_file("$target_gen_dir/$target_name.deps_sources_list", deps_sources)
 
-  generate_fuzzing = enable_ipc_fuzzer && (!defined(invoker.enable_fuzzing) ||
-                                           invoker.enable_fuzzing) &&
-                     (!defined(invoker.testonly) || !invoker.testonly)
+  generate_fuzzing =
+      (!defined(invoker.enable_fuzzing) || invoker.enable_fuzzing) &&
+      enable_ipc_fuzzer && (!defined(invoker.testonly) || !invoker.testonly)
 
   if (sources_list != []) {
     parser_target_name = "${target_name}__parser"