Enable -Wextra-tokens on win clang.

third_party/isimpledom/isimpledom.gyp

 # Copyright (c) 2011 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.
 
 {
   'targets': [
     {
       'target_name': 'isimpledom',
       'type': 'static_library',
       'variables': {
         'midl_out_dir': '<(SHARED_INTERMEDIATE_DIR)/third_party/isimpledom',
+        'clang_warning_flags': [
+          # MIDL generates code like "#endif !_MIDL_USE_GUIDDEF_"
+          '-Wno-extra-tokens',
+        ],
       },
       'sources': [
         'ISimpleDOMDocument.idl',
         'ISimpleDOMNode.idl',
         'ISimpleDOMText.idl',
         '<(midl_out_dir)/ISimpleDOMDocument.h',
         '<(midl_out_dir)/ISimpleDOMDocument_i.c',
         '<(midl_out_dir)/ISimpleDOMNode.h',
         '<(midl_out_dir)/ISimpleDOMNode_i.c',
         '<(midl_out_dir)/ISimpleDOMText.h',
         '<(midl_out_dir)/ISimpleDOMText_i.c',
       ],
       'hard_dependency': 1,
       'direct_dependent_settings': {
         'include_dirs': [
           '<(SHARED_INTERMEDIATE_DIR)',
         ],
       },
       'msvs_settings': {
         'VCMIDLTool': {
           'GenerateTypeLibrary': 'false',
           'OutputDirectory': '<(midl_out_dir)',
         },
       },
     },
   ],
 }