gn win: Add system include directories to midl template

build/toolchain/win/midl.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 assert(is_win)
 
+import("//build/config/win/visual_studio_version.gni")
+
 # This template defines a rule to invoke the MS IDL compiler.
 #
 # Parameters
 #
 #   sources
 #      List of .idl file to process.
 #
 #   out_dir (optional)
 #       Directory to write the generated files to. Defaults to target_gen_dir.
 #
@@ skipping 53 matching lines @@
       type_library_file,
       header_file,
       dlldata_file,
       interface_identifier_file,
       proxy_file,
       "{{source}}",
       "/char", "signed",
       "/env", idl_target_platform,
       "/Oicf",
     ]
+
+    foreach(include, system_include_dirs) {
+      args += [ "/I", include ]
+    }
   }
 
   source_set(target_name) {
     if (defined(invoker.visibility)) {
       visibility = invoker.visibility
     }
 
     # We only compile the IID files from the IDL tool rather than all outputs.
     sources = process_file_template(
         invoker.sources,
         [ "$out_dir/$interface_identifier_file" ])
 
     deps = [ ":$action_name" ]
   }
 }