Persists bubbles to disk (part 1)

Bubbles are now write-through an xml file on disk upon addition/update,
asynchronously.

Bug: 149713060
Test: manually verify when new bubble pops up it is write through xml
Change-Id: I5d9f58cd0858ca96d5ec05c72aad4ae3a18c0aa0
diff --git a/packages/SystemUI/Android.bp b/packages/SystemUI/Android.bp
index b55d246..7a27676 100644
--- a/packages/SystemUI/Android.bp
+++ b/packages/SystemUI/Android.bp
@@ -129,6 +129,8 @@
         "androidx.lifecycle_lifecycle-extensions",
         "androidx.dynamicanimation_dynamicanimation",
         "androidx-constraintlayout_constraintlayout",
+        "kotlinx-coroutines-android",
+        "kotlinx-coroutines-core",
         "iconloader_base",
         "SystemUI-tags",
         "SystemUI-proto",