[Chromecast] Replace architecure-based conditionals with flag.

media/media_options.gni

Index: media/media_options.gni
diff --git a/media/media_options.gni b/media/media_options.gni
index 07b7fdee74d31e5956e9f465c6b12511caaae645..bd78fe661b2e6b48ce1571d49767391b95618a0e 100644
--- a/media/media_options.gni
+++ b/media/media_options.gni
@@ -37,8 +37,8 @@ declare_args() {
 
   # Alsa should be used on non-Android, non-Mac POSIX systems, and Chromecast
   # builds for desktop Linux.
-  if (is_posix && !is_headless && !is_android && !is_mac &&
-      (!is_chromecast || target_cpu != "arm")) {
+  if ((is_posix && !is_headless && !is_android && !is_mac) ||
+      is_cast_dekstop_build) {

[halliwell, 2015/12/15 02:18:46]

fix "dekstop"

[slan, 2015/12/15 03:11:11]

Good catch... turns out the logic wasn't correct either. Fixed.

     use_alsa = true
     if (!use_cras) {
       use_pulseaudio = true