Use libc++ for all non-Windows ASan builds.

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 2068 matching lines @@
       }],
       ['clang_use_chrome_plugins==1 and OS!="win"', {
         'clang_chrome_plugins_flags': [
           '<!@(<(DEPTH)/tools/clang/scripts/plugin_flags.sh)'
         ],
       }],
       ['asan==1 or msan==1 or lsan==1 or tsan==1', {
         'clang%': 1,
         'use_allocator%': 'none',
       }],
-      ['asan==1 and OS=="linux"', {
+      ['asan==1 and OS!="win"', {
         'use_custom_libcxx%': 1,
       }],
       ['ubsan==1', {
         'clang%': 1,
       }],
       ['ubsan_vptr==1', {
         'clang%': 1,
       }],
       ['asan==1 and OS=="mac"', {
         # TODO(glider): we do not strip ASan binaries until the dynamic ASan
@@ skipping 3558 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',
   },
 }