Adds eventlog provider dll to describe the message types of SYSLOG.

base/win/BUILD.gn

Index: base/win/BUILD.gn
diff --git a/base/win/BUILD.gn b/base/win/BUILD.gn
index 01092735b3ae44276cc9180f26876572772c2a5a..017b25acf4e35f16680b9f5267f3e21456f53b27 100644
--- a/base/win/BUILD.gn
+++ b/base/win/BUILD.gn
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build/buildflag_header.gni")
+import("//build/win/message_compiler.gni")
 
 declare_args() {
   # Indicates if the handle verifier should operate in a single module mode. By
@@ -21,3 +22,17 @@ buildflag_header("base_win_features") {
   header_dir = "base/win"
   flags = [ "SINGLE_MODULE_MODE_HANDLE_VERIFIER=$single_module_mode_handle_verifier" ]
 }
+
+message_compiler("eventlog_messages") {
+  visibility = [
+    "//base:base",
+    "//chrome:eventlog_provider",
+  ]
+
+  sources = [
+    "eventlog_messages.mc",
+  ]
+
+  user_mode_logging = false
+  compile_generated_code = false
+}