Bug 1582802 - enable new audio focus management on Android Nightly. r=sebastian

In bug 1565689, we have implemented new an audio focus management, which allows us to address audio competition even if those audio happens on different processes.

We can try to enable this new mechanism on Android Nightly first, where we have enabled managing audio competition by default.

Differential Revision: https://phabricator.services.mozilla.com/D46636

--HG--
extra : moz-landing-system : lando

mobile/android/app/mobile.js

@@ -786,7 +786,13 @@ pref("identity.fxaccounts.remote.oauth.uri", "https://oauth.accounts.firefox.com
 // Token server used by Firefox Account-authenticated Sync.
 pref("identity.sync.tokenserver.uri", "https://token.services.mozilla.com/1.0/sync/1.5");
 
+#ifdef NIGHTLY_BUILD
+// Use new audio focus management, "media.audioFocus.management".
+pref("dom.audiochannel.audioCompeting", false);
+#else
 pref("dom.audiochannel.audioCompeting", true);
+#endif
+
 pref("dom.audiochannel.mediaControl", true);
 pref("media.block-autoplay-until-in-foreground", false);
 

modules/libpref/init/StaticPrefList.yaml

@@ -6131,7 +6131,11 @@
 
 - name: media.audioFocus.management
   type: bool
+#if defined(MOZ_WIDGET_ANDROID) && defined(NIGHTLY_BUILD)
+  value: true
+#else
   value: false
+#endif
   mirror: always
 
 - name: media.hardwaremediakeys.enabled