Add host library for appwidget flags

Adds android.appwidget.flags-aconfig-java-host flag library for use in
app widget host-side tests.

Test: build CtsAppWidgetHostTestCases
Bug: 378016529
Flag: android.appwidget.flags.remote_views_proto
Change-Id: I431ff407b3ad86e7a2ad0ef04556e2c16040f7d4
diff --git a/AconfigFlags.bp b/AconfigFlags.bp
index 371177c..b703018 100644
--- a/AconfigFlags.bp
+++ b/AconfigFlags.bp
@@ -1458,6 +1458,13 @@
     defaults: ["framework-minus-apex-aconfig-java-defaults"],
 }
 
+java_aconfig_library {
+    name: "android.appwidget.flags-aconfig-java-host",
+    aconfig_declarations: "android.appwidget.flags-aconfig",
+    host_supported: true,
+    defaults: ["framework-minus-apex-aconfig-java-defaults"],
+}
+
 // App
 aconfig_declarations {
     name: "android.server.app.flags-aconfig",