Get a minimal unit_tests target building and running for iOS

chrome/common_constants.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
 
   'includes': [
@@ skipping 47 matching lines @@
     {
       'target_name': 'common_constants',
       'type': 'static_library',
       'include_dirs': [
         '<(SHARED_INTERMEDIATE_DIR)',  # Needed by chrome_paths.cc.
       ],
       'dependencies': [
         '../base/base.gyp:base',
         '../third_party/widevine/cdm/widevine_cdm.gyp:widevine_cdm_version_h',
       ],
+      'target_conditions': [
+        ['OS=="ios"', {
+          # iOS needs chrome_paths_mac, which is excluded by filename rules;
+          # re-add it in target_conditionals so it's after that exclusion.
+          'sources/': [
+            ['include', '^common/chrome_paths_mac\\.mm$'],
+          ],
+        }],
+      ],
       'conditions': [
         ['toolkit_uses_gtk == 1', {
           'dependencies': ['../build/linux/system.gyp:gtk'],
         }],
       ],
     },
   ],
   'conditions': [
     ['OS=="win"', {
       'targets': [
@@ skipping 14 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }