Move performance mode to top app

Change-Id: I436102b4f8d046b8f3d897882613ec46acf9e2c5
diff --git a/update_attempter_android.cc b/update_attempter_android.cc
index bb2d86a..9fb7bf1 100644
--- a/update_attempter_android.cc
+++ b/update_attempter_android.cc
@@ -434,7 +434,7 @@
 
   if (performance_mode_ == enable)
     return true;
-  if (set_cpuset_policy(0, enable ? SP_FOREGROUND : SP_BACKGROUND) < 0)
+  if (set_cpuset_policy(0, enable ? SP_TOP_APP : SP_BACKGROUND) < 0)
     return LogAndSetError(error, FROM_HERE, "Could not change policy");
   performance_mode_ = enable;
   return true;