GN: Make chrome/{browser,common,renderer} compile on mac

media/media_options.gni

 # 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.
 
 # These variables need to be args.
 
 # Override to dynamically link the cras (ChromeOS audio) library.
 use_cras = false
 
 # Option e.g. for Linux distributions to link pulseaudio directly
 # (DT_NEEDED) instead of using dlopen. This helps with automated
 # detection of ABI mismatches and prevents silent errors.
 #
 # TODO(ajwong): Why is this prefixed "linux_"?
 linux_link_pulseaudio = false
 
 # TODO(ajwong): Enable libvpx once that's converted.
 media_use_ffmpeg = true
 media_use_libvpx = false
 if (is_android) {
   # Android doesn't use ffmpeg or libvpx.
   media_use_ffmpeg = false
   media_use_libvpx = false
 }
 
 # TODO(ajwong): how to disable embedded?
 # Original conditional: (OS=="linux" or OS=="freebsd" or OS=="solaris") and embedded!=1
 use_alsa = false
 use_pulseaudio = false
-if (is_posix && !is_android) {
+if (is_posix && !is_android && !is_mac) {
   use_alsa = true
   if (!use_cras) {
     use_pulseaudio = true
   }
 }
 
 # TODO(ajwong): is_openbsd should be a platform define.
 is_openbsd = false
 
 # TODO(ajwong): This should be branding controlled?
 proprietary_codecs = false
 
 # TODO(ajwong): Where are these coming from?jk
 enable_mpeg2ts_stream_parser = false
 enable_browser_cdms = is_android