[chromcast] Still need to call StreamMixerAlsa::SetVolume, even when ALSA doesn't own the volume.

chromecast/media/cma/backend/alsa/BUILD.gn

Index: chromecast/media/cma/backend/alsa/BUILD.gn
diff --git a/chromecast/media/cma/backend/alsa/BUILD.gn b/chromecast/media/cma/backend/alsa/BUILD.gn
index 2838a6d342b2fdc4b5add9df7e3095025252951d..3552bc4c6c491185cea0330e7ce5861569488eeb 100644
--- a/chromecast/media/cma/backend/alsa/BUILD.gn
+++ b/chromecast/media/cma/backend/alsa/BUILD.gn
@@ -110,14 +110,14 @@ source_set("slew_volume") {
   ]
 }
 
-alsa_controls_volume = !enable_assistant
+alsa_owns_volume = !enable_assistant
 
 buildflag_header("alsa_features") {
   header = "alsa_features.h"
 
   flags = [
     "ALSA_MONOTONIC_RAW_TSTAMPS=$use_alsa_monotonic_raw_tstamps",
-    "ALSA_CONTROLS_VOLUME=$alsa_controls_volume",
+    "ALSA_OWNS_VOLUME=$alsa_owns_volume",
   ]
 }