clang/win: Don't pass -Wno-inconsistent-missing-override twice.

build/common.gypi

 # Copyright (c) 2012 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 2574 matching lines @@
         # initializer lists (e.g. |int a = f(); CGSize s = { a, a };|),
         # which happens in several places in chrome code. Not sure if
         # this is worth fixing.
         '-Wno-c++11-narrowing',
 
         # Clang considers the `register` keyword as deprecated, but e.g.
         # code generated by flex (used in angle) contains that keyword.
         # http://crbug.com/255186
         '-Wno-deprecated-register',
 
-        # TODO(hans): Get this cleaned up.
+        # TODO(hans): Get this cleaned up, http://crbug.com/428099
         '-Wno-inconsistent-missing-override',
       ],
     },
     'includes': [ 'set_clang_warning_flags.gypi', ],
     'defines': [
       # Don't use deprecated V8 APIs anywhere.
       'V8_DEPRECATION_WARNINGS',
     ],
     'include_dirs': [
       '<(SHARED_INTERMEDIATE_DIR)',
@@ skipping 3118 matching lines @@
                   '-Wno-sometimes-uninitialized',
                   '-Wno-switch',
                   '-Wno-tautological-compare',
                   '-Wno-unknown-pragmas',
                   '-Wno-unsequenced',
                   '-Wno-unused-function',
                   '-Wno-unused-private-field',
                   '-Wno-unused-value',
                   '-Wno-unused-variable',
                   '-Wno-unused-local-typedef',  # http://crbug.com/411648
-                  '-Wno-inconsistent-missing-override',  # http://crbug.com/428099
                 ],
               },
             }],
             ['clang==1 and target_arch=="ia32"', {
               'VCCLCompilerTool': {
                 'WarnAsError': 'false',
                 'AdditionalOptions': [
                   '/fallback',
                 ],
               },
@@ skipping 456 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }