Add "stylus-tools" Wayland protocol.

third_party/wayland-protocols/BUILD.gn

Index: third_party/wayland-protocols/BUILD.gn
diff --git a/third_party/wayland-protocols/BUILD.gn b/third_party/wayland-protocols/BUILD.gn
index 474fd13a115c8403a282e469195de8d78a7f905d..99bb828771ca2bd12b9f8fd0177cfd278e4396ee 100644
--- a/third_party/wayland-protocols/BUILD.gn
+++ b/third_party/wayland-protocols/BUILD.gn
@@ -241,3 +241,24 @@ source_set("keyboard_configuration_protocol") {
 
   public_configs = [ ":keyboard_configuration_protocol_config" ]
 }
+
+config("annotation_protocol_config") {
+  include_dirs = [ "include/protocol" ]
+}
+
+source_set("annotation_protocol") {
+  sources = [
+    "include/protocol/annotation-unstable-v1-client-protocol.h",
+    "include/protocol/annotation-unstable-v1-server-protocol.h",
+    "protocol/annotation-protocol.c",
+  ]
+
+  deps = [
+    "//third_party/wayland:wayland_util",
+  ]
+
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [ "//build/config/compiler:no_chromium_code" ]
+
+  public_configs = [ ":annotation_protocol_config" ]
+}