Keep smartspace session object

The object was getting prematurely optimized out because it wasn't referenced
in code later, but it is necessary to keep alive in order to get
recommendation updates.
Add annotation to make sure it's kept, and explicitly close when destroy
is called

Bug: 273739913
Bug: 283493228
Test: manual - verify session is not destroyed after restarting SysUI
Change-Id: I98bd7ce5878f9f261e1c09673faaae35e954f173

packages/SystemUI/src/com/android/systemui/media/controls/pipeline/MediaDataManager.kt

@@ -52,6 +52,7 @@ import android.text.TextUtils
 import android.util.Log
 import android.util.Pair as APair
 import androidx.media.utils.MediaConstants
+import com.android.internal.annotations.Keep
 import com.android.internal.logging.InstanceId
 import com.android.internal.statusbar.IStatusBarService
 import com.android.keyguard.KeyguardUpdateMonitor
@@ -220,7 +221,7 @@ class MediaDataManager(
     private val mediaEntries: LinkedHashMap<String, MediaData> = LinkedHashMap()
     // There should ONLY be at most one Smartspace media recommendation.
     var smartspaceMediaData: SmartspaceMediaData = EMPTY_SMARTSPACE_MEDIA_DATA
-    private var smartspaceSession: SmartspaceSession? = null
+    @Keep private var smartspaceSession: SmartspaceSession? = null
     private var allowMediaRecommendations = allowMediaRecommendations(context)
 
     private val artworkWidth =
@@ -380,6 +381,8 @@ class MediaDataManager(
 
     fun destroy() {
         smartspaceMediaDataProvider.unregisterListener(this)
+        smartspaceSession?.close()
+        smartspaceSession = null
         context.unregisterReceiver(appChangeReceiver)
     }