Reland https://codereview.chromium.org/581983003/: Enable ASan default options on Mac.

build/sanitizers/sanitizers.gyp

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'sanitizer_options',
       'type': 'static_library',
       'toolsets': ['host', 'target'],
@@ skipping 27 matching lines @@
         }],
       ],
       'cflags/': [
         ['exclude', '-fsanitize='],
         ['exclude', '-fsanitize-'],
       ],
       'direct_dependent_settings': {
         'ldflags': [
           '-Wl,-u_sanitizer_options_link_helper',
         ],
+        'target_conditions': [
+          ['_type=="executable"', {
+            'xcode_settings': {
+              'OTHER_LDFLAGS': [
+                '-Wl,-u,__sanitizer_options_link_helper',
+              ],
+            },
+          }],
+        ],
       },
     },
   ],
 }