Warn on missing OVERRIDE/virtual everywhere, not just in header files.

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 1508 matching lines @@
       ['enable_settings_app==1', {
         'grit_defines': ['-D', 'enable_settings_app'],
       }],
       ['enable_google_now==1', {
         'grit_defines': ['-D', 'enable_google_now'],
       }],
       ['use_concatenated_impulse_responses==1', {
         'grit_defines': ['-D', 'use_concatenated_impulse_responses'],
       }],
       ['clang_use_chrome_plugins==1 and OS!="win"', {
-        'clang_chrome_plugins_flags': [
-          '<!@(<(DEPTH)/tools/clang/scripts/plugin_flags.sh)'
+        'variables': {
+          'clang_chrome_plugins_flags': [
+            '<!@(<(DEPTH)/tools/clang/scripts/plugin_flags.sh)'
+          ],
+        },
+        'conditions': [
+          ['OS=="linux" and chromeos==0', {
+            'clang_chrome_plugins_flags': [
+              '<@(clang_chrome_plugins_flags)'
+            ],
+          }, {
+            # TODO(rsleevi): http://crbug.com/115047 - This warning is only
+            # enabled for Linux for now. Disable everywhere else.
+            'clang_chrome_plugins_flags': [
+              '<@(clang_chrome_plugins_flags)',
+              '-Xclang',
+              '-plugin-arg-find-bad-constructs',
+              '-Xclang',
+              'skip-virtuals-in-implementations',
+            ],
+          }]
         ],
       }],
 
       ['asan==1 and OS!="win"', {
         'clang%': 1,
       }],
       ['asan==1 and OS=="mac"', {
         # See http://crbug.com/145503.
         'component': "static_library",
         # TODO(glider): we do not strip ASan binaries until the dynamic ASan
@@ skipping 2859 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',
   },
 }