[Chromecast] Enable MultizoneBackendTest on Earth.

chromecast/chromecast.gni

Index: chromecast/chromecast.gni
diff --git a/chromecast/chromecast.gni b/chromecast/chromecast.gni
index 64d3f74bc14ea7e6337a939d4cd2f3354154b655..41a20d4164fbad8168a22aacf44ba5fd60329dab 100644
--- a/chromecast/chromecast.gni
+++ b/chromecast/chromecast.gni
@@ -36,6 +36,11 @@ declare_args() {
 
   # Set true to enable assistant features.
   enable_assistant = false
+
+  # Set to true on devices that support multizone. Only indicates that the
+  # device supports multizone. The command line flag --enable-multizone must
+  # still be used to enable multizone.
+  supports_multizone = is_cast_audio_only

[kmackay, 2017/06/03 02:59:48]

Note, this will change the behaviour a bit since it turns on multizone backend
unittests for desktop audio builds (which I assume will break).

[jameswest, 2017/06/03 03:07:51]

I restored the check for not desktop in the condition for the multizone backend
tests.

[kmackay, 2017/06/03 03:14:31]

Is that really accurate though (ie, does desktop actually support multizone)?

[jameswest, 2017/06/05 19:45:22]

I changed it to default to false for desktop builds because I think the
multizone backend tests should pass whenever supports_multizone is true. 

 }
 
 declare_args() {