Inflate notification content on a dedicated thread

We're worried that incoming call notifications might be getting delayed
by other background activity, so we're moving notification content
inflation to a dedicated background thread.

Bug: 308967184
Flag: ACONFIG dedicated_notification_inflation_thread DEVELOPMENT
Test: existing notification tests
Change-Id: I4f6331bf3ae21ae5871a6f16f6235af2412950c5
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index a0dd922..71f9ba27 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -519,3 +519,13 @@
         purpose: PURPOSE_BUGFIX
     }
 }
+
+flag {
+    name: "dedicated_notif_inflation_thread"
+    namespace: "systemui"
+    description: "Create a separate background thread for inflating notifications"
+    bug: "308967184"
+    metadata {
+        purpose: PURPOSE_BUGFIX
+    }
+}