Fix starting the download service in the background throw exception

This happens when the device screen is locked.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=198875192

demos/main/src/main/java/com/google/android/exoplayer2/demo/SampleChooserActivity.java

@@ -95,8 +95,16 @@ public class SampleChooserActivity extends Activity
     loaderTask.execute(uris);
     loaderTask.execute(uris);
 
 
     // Ping the download service in case it's not running (but should be).
     // Ping the download service in case it's not running (but should be).
-    startService(
-        new Intent(this, DemoDownloadService.class).setAction(DownloadService.ACTION_INIT));
+    Intent serviceIntent =
+        new Intent(this, DemoDownloadService.class).setAction(DownloadService.ACTION_INIT);
+    // Starting the service in the foreground causes notification flicker if there is no scheduled
+    // action. Starting it in the background throws an exception if the app is in the background too
+    // (e.g. if device screen is locked).
+    try {
+      startService(serviceIntent);
+    } catch (IllegalStateException e) {
+      startForegroundService(serviceIntent);
+    }
   }
   }
 
 
   @Override
   @Override